Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

Why is day trading considered riskier than long-term trading?
Over a period of time greater than 10 years (keep in mind, 2000-2009 ten year period fails, so I am talking longer) the market, as measured by the S&P 500, was positive. Long term, averaging more than 10%/yr.  At a 1 year horizon, the success is 67 or so percent. It's mostly for this reason that those asking about investing are told that if they need money in a year or two, to buy a house for instance, they are told to stay out of the market.  As the time approaches one day or less, the success rate drops to 50/50. The next trade being higher or lower is a random event.  Say you have a $5 commission. A $10,000 trade buy/sell is $10 for the day. 250 trading days costs you $2500 if you get in and out once per day. You need to be ahead 25% for the year to break even.  You can spin the numbers any way you wish, but in the end, time (long time spans) is on your side.