The most important thing is to remember that every time you buy stocks, somebody is selling them to you, and every time you sell, somebody is buying them from you. Unless you're a pro, or have at least educated yourself deeply on stock picking, do you really think you'll be making better buy and sell decisions than pros who have a deep bench of analysts supporting them? The better way for most investors is to educate themselves on picking superior mutual fund managers and then invest in their funds.