Dollar-cost averaging: How often should one use it? What criteria to use when choosing stocks to apply it to?
"Why do people keep talking about 401K's at work?  That is NOT dollar cost averaging.  DCA refers to when you have a large sum of money.  Do you invest it all at once or spread it out over several smaller purchases over a period of time?  There really isn't a ""when"" should I use it.  It is simply a matter of where your preferences lie on the risk/reward scpectrum.  DCA has lower risk and lower reward than lump sum investing.  In my opinion, I don't like it.  DCA only works better than lump sum investing if the price drops.  But if you think the price is going to drop, why are you buying the stock in the first place? Example: Your uncle wins the lottery and gives you $50,000.  Do you buy $50,000 worth of Apple now, or do you buy $10,000 now and $10,000 a quarter for the next four quarters? If the stock goes up, you will make more with lump-sum(LS) than you will with DCA. If the stock goes down, you will lose more with LS than you will with DCA. If the stock goes up then down, you will lose more with DCA than you will with LS. If the stock goes down then up, you will make more with DCA than you will with LS. So it's a tradeoff.  But, like I said, the whole point of you buying the stock is that you think it's going to go up! So why pick the strategy that performs worse in that scenario?" Dollar cost averaging is a great strategy to use for investment vehicles where you can't invest it in a lump sum. A 401K is perfect for this. You take a specific amount out of each paycheck and invest it either in a single  fund, or multiple funds, or some programs let you invest it in a brokerage account so you can invest in virtually any mutual fund or stock. With annual or semi-annual re-balancing of your investments dollar cost averaging is the way to invest in these programs. If you have a lump sum to invest, then dollar cost averaging is not the best way to invest. Imagine you want to invest 10K and you want to be 50% bonds and 50% stocks. Under dollar cost averaging you would take months to move the money from 100% cash to 50/50 bonds/stocks. While you are slowly moving towards the allocation you want, you will spend months not in the allocation you want. You will spend way too long in the heavy cash position you were trying to change. The problem works the other way also. Somebody trying to switch from stocks to gold a few years ago, would not have wanted to stay in limbo for months. Obviously day traders don't use dollar cost averaging. If you will will be a frequent trader, DCA is not the way to go.  No particular stock type is better for DCA. It is dependent on how long you plan on keeping the investment, and if you will be working with a lump sum or not. EDIT: There have be comments regarding DCA and 401Ks. When experts discuss why people should invest via a 401K, they mention DCA as a plus along with the company match. Many participants walk away with the belief that DCA is the BEST strategy. Many articles have been written about how to invest an inheritance or tax refund, many people want to use DCA because they believe that it is good. In fact in the last few years the experts have begun to discourage ever using DCA unless there is no other way. "How often should one use dollar-cost averaging? Trivially, a dollar cost averaging (DCA) strategy must be  used at least twice! More seriously, DCA is a discipline that people (typically investors with relatively small amounts of money to invest each month or each quarter)  use to avoid succumbing to the temptation to ""time the market"".  As mhoran_psprep points out, it is well-suited to 401k plans and the like (e.g. 403b plans for educational and non-profit institutions, 457 plans for State employees, etc), and indeed is actually  the default option in such plans, since a fixed amount of money gets invested each week, or every  two weeks, or every month depending on the payroll schedule. Many plans offer just a few mutual funds in which to invest, though far too many people, having little knowledge or understanding of  investments, simply opt for the money-market fund or guaranteed annuity fund in their 4xx plans.  In any case, all your money goes to work immediately since all mutual funds let you invest in thousandths of a share. Some 401k/403b/457 plans allow investments in stocks through a brokerage, but I think that using DCA to  buy individual stocks in a retirement plan is not a good  idea at all. The reasons for this are that not only must shares must be bought in whole numbers (integers) but it is generally cheaper to buy stocks in round lots  of 100 (or multiples of 100) shares rather than in odd lots of, say, 37 shares. So buying stocks weekly, or biweekly or monthly in a 401k plan means paying more or having the money sit idle until enough is accumulated to buy 100 shares of a stock at which point the brokerage executes the order to buy the stock; and this is really not DCA at all.  Worse yet, if you let the money accumulate but you are the one calling the shots ""Buy 100 shares of APPL today"" instead of letting the brokerage execute the order when there is enough money, you are likely to  be timing the market instead of doing DCA. So, are brokerages useless in retirement fund accounts?  No, they can be useful but they are not suitable for DCA strategies involving buying stocks. Stick to mutual funds for DCA. Do people use it across the board on all stock investments? As indicated above, using DCA to buy individual stocks is not the best idea, regardless of whether it is done inside a retirement plan or outside. DCA outside a retirement plan works best if you not trust yourself to stick with the strategy (""Ooops, I forgot to mail the check yesterday; oh, well, I will do it next week"") but rather, arrange for your mutual fund company to take the money out of your checking account each week/month/quarter etc, and invest it in whatever fund(s) you have chosen. Most companies have such programs under names such as Automatic Investment Program (AIP) etc. Why not have your bank send the money to the mutual fund company instead? Well, that works too, but my bank charges me for sending the money whereas my mutual fund company does AIP for free. But YMMV. Dollar-cost averaging generally means investing  a fixed amount of money on a periodic basis. An alternative strategy, if one has decided that owning 1200 shares of FlyByKnight Co is a good investment to have, is to buy round lots of 100 shares of FBKCO each month. The amount of money invested each month varies, but at the end of the year, the average cost of the 1200 shares is the average of the prices on the 12 days on which the investments were made. Of course, by the end of the year, you might not think FBKCO is worth holding any more. This technique worked best in the  ""good old days"" when blue-chip stocks  paid what was for all practical purposes a guaranteed dividend each year, and people bought these stocks with the intention of passing them on to their widows and children." Dollar cost averaging can be done in a retirement plan, and can be done for individual stock purchases, as this will increase your returns by reducing your risk, especially if you are buying a particular stock for the first time.   How many time have I purchased a stock, bottom fishing, thinking I was buying at the low, only to find out there was a new low.  Sitting with a thousand shares that are now down $3-$4K.  I have a choice to sell at a loss, hold what I've got or double down.  I usually add more shares if I'm thinking I'll recover, but at that time I'd wished I'd eased into my investment.  That way I would have owned more shares at a smaller cost basis.   Anything can happen in the market, not knowing whether the price will increase or decrease.  In the example above a $3,000 loss is equal to the brokerage cost of about 300 trades, so trading cost should not be a factor.  Now I'm not saying to slowly get into the market and miss the bull, like we're having today with Trump, but get into individual stocks slowly, being fully invested in the market.   Also DCA means you do not buy equal number of shares per period, say monthly, but that you buy with the same amount of money a different number of shares, reducing your total costs.  Let's say you spend $2000 on a stock trading at $10 (200 shares), if the stock rose to $20 you would spend $2000 and buy 100 shares, and if the stock dropped to $5 you would spend $2000 and buy 400 shares, by now having amassed 700 shares for $6,000.  On the other hand and in contrast to DCA had you purchased 200 shares for $2000 at $10/share, then 200 shares for $4000 at $20/share, and finally 200 more shares for $1000 at $5/share, you would have amassed only 600 shares for $7000 investment.
The idea of an index is that it is representative of the market (or a specific market segment) as a whole, so it will move as the market does. Thus, past performance is not really relevant, unless you want to bank on relative differences between different countries' economies. But that's not the point. By far the most important aspect when choosing index funds is the ongoing cost, usually expressed as Total Expense Ratio (TER), which tells you how much of your investment will be eaten up by trading fees and to pay the funds' operating costs (and profits). This is where index funds beat traditional actively managed funds - it should be below 0.5% The next question is how buying and selling the funds works and what costs it incurs. Do you have to open a dedicated account or can you use a brokerage account at your bank? Is there an account management fee? Do you have to buy the funds at a markup (can you get a discount on it)? Are there flat trading fees? Is there a minimum investment? What lot sizes are possible? Can you set up a monthly payment plan? Can you automatically reinvest dividends/coupons?  Then of course you have to decide which index, i.e. which market you want to buy into. My answer in the other question apparently didn't make it clear, but I was talking only about stock indices. You should generally stick to broad, established indices like the MSCI World, S&P 500, Euro Stoxx, or in Australia the All Ordinaries. Among those, it makes some sense to just choose your home country's main index, because that eliminates currency risk and is also often cheaper. Alternatively, you might want to use the opportunity to diversify internationally so that if your country's economy tanks, you won't lose your job and see your investment take a dive. Finally, you should of course choose a well-established, reputable issuer. But this isn't really a business for startups (neither shady nor disruptively consumer-friendly) anyway. "Two main points to answer this in my opinion. First, most people don't start with say half a million dollar to buy all the stocks they need in one shot but rather they accumulate this money gradually. So they must make many Buys in their lifetime. Similarly, most people don't need to withdraw all their investment in one day (and shouldn't do this anyway as it cuts the time of investment). So there will be many Sells. Performing a single buy or sell per year is not efficient since it means you have lots of cash sitting doing nothing. So in this sense, low cost indexing lets you quickly invest your money (and withdraw it when needed after say you retire) without worrying about commission costs each time. The second and most important point to me to answer this is that we should make a very clear distinction between strategy and outcome. Today's stock prices and all the ups and downs of the market are just one possible outcome that materialized from a virtually uncountable number of possible outcomes. It's not too hard to imagine that tomorrow we hear all iPhones explode and Apple stock comes crashing down. Or that in a parallel universe Amazon never takes off and somehow Sears is the king of online commerce. Another item in the ""outcome"" category is your decisions as a human being of when to buy and sell. If that exploding iPhone event does occur, would you hold on to your stocks? Would you sell and cut your losses? Does the average person make the same decision if they had $1000 invested in Apple alone vs $1M?  Index investing offers a low cost strategy that mitigates these uncertainties for the average person. Again here the key is the word ""average"". Picking a handful of the heavyweight stocks as you mention might give you better returns in 30 years, but it could just as easily give you worse. And the current data suggest the latter is more likely. ""Heavyweights"" come and go (who were they 30 years ago?) and just like how the other 450 companies may seem right now as dragging down the portfolio, just as easily a handful of them can emerge as the new heavyweights. Guaranteed? No. Possible? Yes.  Jack Bogle is simply saying low cost indexing is one of the better strategies for the average person, given the data. But nowhere is it guaranteed that in this lifetime (e.g. next 30 years) will provide the best outcome. Berkshire on the other hand are in the business of chasing maximum outcomes (mid or short term returns). It's two different concepts that shouldn't be mixed together in my opinion." "The biggest (but still temporary) ding you'll see on your credit score from opening a new account is from the low average (and low minimum) account age.  This will have a stronger effect than the hard pull of the credit report, which is still a factor (but not much of one if you only have 1-2 pulls in the past couple years).   Having a lower average account age increases your risk to lenders.  Your average will go up by one month per month, and each time you open an account it will suffer a drop proportional to the number of accounts you already had open before.  So if you want to have a more ""solid"" credit score that stays strong in the face of new accounts in the future, it's better to open a few more accounts now (assuming you can ride out the temporary drop in score and aren't planning to go e.g. mortgage-shopping in the very near future).   Having an additional line of credit will also likely cause your credit card utilization (total balance / total credit limit, expressed as a percentage) to decrease, which would tend to increase your credit score, counteracting the age factor, unless your utilization is already extremely low (which it probably is given your monthly account payoffs).  There are various credit score simulators out there, from places that show you your credit score, and you can put in a hypothetical new card account to see the immediate likely impact for your particular situation.   You identified other costs, such as risk of fraud and fees.  You should check your statements once in a while even if you're not using the card, just to make sure no one else is.  The bit of additional time required for this is a nonzero cost of having an open credit card account.  So is the additional hassle of dealing with having the card stolen etc. if you carry it in your wallet and your wallet's stolen. If you have an account with zero activity for some number of years, the bank may close it automatically and that can reflect negatively on a credit report (as a bank closure of the account, the reason is often obscured).  Check your terms and conditions and/or have some activity every so often to prevent this from happening.   Some of the otherwise most attractive credit cards have monthly or annual fees, which will cost you, and you won't want to close those because it would then reduce your credit score (e.g. by reducing the total available credit and increasing your utilization percentage) - so the solution is don't apply for credit cards that have monthly/annual fees.  There are plenty of good cards without those fees. With a credit score that high, you can get cards that have some very good benefits and rewards programs, as well as some with great introductory offers.  Though I'm not familiar with details of Amazon's offer, $80 cash up-front with nothing else seems unlikely to be among your best options.  I would think that for at least some of the fee-free cards available to you, the benefits exceed the costs, and you could ""cash in"" some of the benefits of your good credit record to get those benefits (i.e. this is one of those things you work hard to build good credit for), while also building your long-term reputation for repayment reliability.   Also be aware as you shop around for cards that credit card companies pay fairly high referral fees to websites that send customers their way, so if you want you can think about who you're supporting when you click the link that takes you to an application you complete, and choose to support a site you think is providing a useful consumer-focused service.   As factors affecting your credit score in addition to payment history (i.e. making regular payments as agreed on the new account will help you), Equifax lists:" NSCC illiquid charges are charges that apply to the trading of low-priced over-the counter (OTC) securities with low volumes. Open net buy quantity represents the total unsettled share amount per stock at any given time during a 3-day settlement cycle. Open net buy quantity must be less than 5,000,000 shares per stock for your entire firm Basically, you can't hold a long position of more than 5 million shares in an illiquid OTC stock without facing a fee. You'll still be assessed this fee if you accumulate a long position of this size by breaking your purchase up into multiple transactions. Open net sell quantity represents the total unsettled share amount per stock at any given time during a 3-day settlement cycle. Open net sell quantity must be less than 10% percent of the 20-day average volume If you attempt to sell a number of shares greater than 10% of the stock's average volume over the last 20 days, you'll also be assessed a fee. The first link I included above is just an example, but it makes the important point: you may still be assessed a fee for trading OTC stocks even if your account doesn't meet the criteria because these restrictions are applied at the level of the clearing firm, not the individual client.  This means that if other investors with your broker, or even at another broker that happens to use the same clearing firm, purchase more than 5 million shares in an individual OTC stock at the same time, all of your accounts may face fees, even though individually, you don't exceed the limits. Technically, these fees are assessed to the clearing firm, not the individual investor, but usually the clearing firm will pass the fees along to the broker (and possibly add other charges as well), and the broker will charge a fee to the individual account(s) that triggered the restriction. Also, remember that when buying OTC/pink sheet stocks, your ability to buy or sell is also contingent on finding someone else to buy from/sell to. If you purchase 10,000 shares one day and attempt to sell them sometime in the future, but there aren't enough buyers to buy all 10,000 from you, you might not be able to complete your order at the desired price, or even at all. The optimal time period is unambiguously zero seconds.  Put it all in immediately.  Dollar cost averaging reduces the risk that you will be buying at a bad time (no one knows whether now is a bad or great time), but brings with it reduction in expected return because you will be keeping a lot of money in cash for a long time.  You are reducing your risk and your expected return by dollar cost averaging. It's not crazy to trade expected returns for lower risk.  People do it all the time.  However, if you have a pot of money you intend to invest and you do so over a period of time, then you are changing your risk profile over time in a way that doesn't correspond to changes in your risk preferences.  This is contrary to finance theory and is not optimal.  The optimal percentage of your wealth invested in risky assets is proportional to your tolerance for risk and should not change over time unless that tolerance changes. Dollar cost averaging makes sense if you are setting aside some of your income each month to invest.  In that case it is simply a way of being invested for as long as possible.  Having a pile of money sitting around while you invest it little by little over time is a misuse of dollar-cost averaging. Bottom line: forcing dollar cost averaging on a pile of money you intend to invest is not based in sound finance theory.  If you want to invest all that money, do so now.  If you are too risk averse to put it all in, then decide how much you will invest, invest that much now, and keep the rest in a savings account indefinitely.  Don't change your investment allocation proportion unless your risk aversion changes. There are many people on the internet and elsewhere who preach the gospel of dollar cost averaging, but their belief in it is not based on sound principles.  It's just a dogma. The language of your question implies that you may be interested in sound principles, so I have given you the real answer. Common financial advice is just that - it is common and general in nature and not specific for your financial needs, your goals and your risk tolerance. Regarding the possibility of a US market not going anywhere over a long period of time, well it is not a possibility, it has happened. See chart below:  It took 13 years for the S&P 500 to break through 1550, a level first reached in March 2000, tested in October 2007 (just before the GFC) and finally broken through in March 2013. If you had bought in early 2000 you would still be behind when you take inflation into account. If you took the strategy of dollar cost averaging and bought the same dollar value (say $10,000) of the index every six months (beginning of each January and each July) starting from the start of 2000 and bought your last portion in January 2013, you would have a return of about 35% over 13.5 years (or an average of 2.6% per year). Now lets look at the same chart below, but this time add some trend lines.  If we instead bought whenever the price crossed above the downtrend-line and sold whenever the price crossed below the uptrend-line (with the first purchase at the start of January 2000), we would have a return of 93% over the 13.5 years (or an average of 6.9% per year). Another more aggressive option (but manageable if you incorporate a risk management strategy) is to buy long when the price crosses the downtrend-line and sell your existing long position and sell short when the price drops below the uptrend-line. That is profiting both up-trending and down-trending markets. Again we start our buying at the start of January 2000. By shorting the index when the market is in a down-trend you could increase the above returns of 93% by another 54%, for a total return of 147% over 13.5 years (or an average of 10.9% per year). To conclude, using a simple long term strategy to time the markets may result in considerably higher returns than dollar cost averaging over the medium to long term, and I know which strategy would help me sleep better at night. About 3.87% annualized, actually. But hey, let's get a head start and since the DOW is a price-weighted average, we could swap out the lowest priced stocks on the DOW (i.e. Pfizer and Cisco) with Berkshire Hathaway A shares and Amazon. Presto! The DOW is dumb. "One idea: If you came up with a model to calculate a ""fair price range"" for a stock, then any time the market price were to go below the range it could be a buy signal, and above the range it could be a sell signal. There are many ways to do stock valuation using fundamental analysis tools and ratios: dividend discount model, PEG, etc. See Wikipedia - Stock valuation. And while many of the inputs to such a ""fair price range"" calculation might only change once per quarter, market prices and peer/sector statistics move more frequently or at different times and could generate signals to buy/sell the stock even if its own inputs to the calculation remain static over the period. For multinationals that have a lot of assets and income denominated in other currencies, foreign exchange rates provide another set of interesting inputs. I also think it's important to recognize that with fundamental analysis, there will be extended periods when there are no buy signals for a stock, because the stocks of many popular, profitable companies never go ""on sale"", except perhaps during a panic. Moreover, during a bull market and especially during a bubble, there may be very few stocks worth buying. Fundamental analysis is designed to prevent one from overpaying for a stock, so even if there is interesting volume and price movement for the stock, there should still be no signal if that action happens well beyond the stock's fair price. (Otherwise, it isn't fundamental analysis — it's technical analysis.) Whereas technical analysis can, by definition, generate far more signals because it largely ignores the fundamentals, which can make even an overvalued stock's movement interesting enough to generate signals."