Investors... can't pick stocks that are better than average. Stocks are a good thing to own over time. There's only two things you can do wrong: You can buy the wrong ones, and you can buy or sell them at the wrong time. And the truth is you never need to sell them.
Warren Buffett... but the important thing is that when you do find one where you really do know what you are doing, you must buy in quantity.... Charlie and I have made a dozen or so very big decisions relative to net worth, although not as big as they should have been. And in each of those, we've known that we were almost certain to be right going in.
Warren Buffett