[nerdponx]

It's not a dumb question, frankly. But the saying is that "the markets can stay irrational longer than you can stay solvent". Yes, if you time the market by selling high and re-buying low, you can make more money. But the general advice is not to sell because a typical market participant isn't going to be able to time the market.

That said, I don't believe in the efficient market hypothesis, so I think people who claim that you can't time the market at all are either wrong or lying.

[imtringued]

Yeah sure but if you have the ability to time the market then you wouldn't ask this question in the first place. You'd spend your day working 40 hours a week managing million dollar portfolios. Therefore telling people they can't time the market is perfectly good advice.