No question, it is impossible to know the top or the bottom. For that matter, how long it will take to get to the bottom, back to the top, etc. But I'm personally gambling that the market will not soar even higher in the next few years. Even if it does, at some point I see it going way down again. I wouldn't wait for the bottom, since we have no idea what it is. Just buy chunks on the way down once we get to correction territory. I just don't believe in dollar cost averaging for stocks. There is always some luck, some educated guessing involved, but I believe we've had a big bad bull market, and I'm not buying equities until we have a correction. Yea, that means I have to wait, maybe for a while, but that's ok.