I used to do that. Big mistake trying to time the market...buying and selling the same stock over and over again trying to make a bigger overall profit is a costly mistake. That kind of trading is not a good strategy and usually fails due to gap ups / gap downs at the open. Did that with BAC last year. Better to buy and hold until stock nears your target price.
What are you talking about? Timing the market is a big mistake? I used to think buy and hold was the way to go, but it got me nowhere quick. Then I started analyzing and timing the market and I made a little over 1.8 million in one year. And, no, I didn't sell my 77k shares yet that I bought at 8.99 on Tuesday. No, I don't always buy at the lowest dollar, and I don't always sell at the highest dollar, but I make a #$%$ load of money in the process.