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

Why invest for the long-term rather than buy and sell for quick, big gains?
Every time you buy or sell a share for some price, somebody must have thought that that was exactly the right moment to sell or buy that share at that price (and to trade with you). Every time a trade is made, both sides think they are doing the smart thing. Most of the time, one will turn out to be wrong, the other right. Nothing in your proposed method of trading explains why you would be the side that was right more often. So they'll probably even out. Or maybe there are people in the market who actually do have a slightly better than average method, and you'll be wrong somewhat more often than right. Each trade has transaction costs. If you simply hang on to your shares, that's more or less the same as evening out good trades and bad trades, but without the transaction costs.