I am aware that our markets have not yet recovered their highs from a few years ago. Other markets like Japan's haven't recovered from the 80's. But let's say you have a hypothetical account size - $500,000. Then assume worst case scenario for the US market is a 50% drawdown. I realize we dropped farther in 2009, and I'm not saying it won't/can't happen again. For the sake of this example, it won't matter. SPY closed at $134 and change today, so we'll use that as our starting point. When it drops by certain intervals, we buy. Whatever that interval may be determines your buy size. Say it's a $1 interval. Assuming 50% worst case drawdown, that's a potential $67 fall. So, $500,000/67 intervals = almost $7500 per buy. For every $1 fall in the SPY, you'd buy $7500 worth of shares. You sell when you get back to your starting point. In this case, $134. Then you start over and wait for the falls again. If today's $134 is the high on the SPY before a fall to $67, well, you'd eventually be in at an average cost of about $100 and theoretically out of money. Unless you kept a % of your assets elsewhere for some diversification. Probably smart. Of course the $1 increment could be 1% or 5% and maybe you progressively buy higher amounts on the way down, whatever. It's just a most basic averaging down strategy if there ever was one. And I realize that. But from a long-term perspective - no day-trading here - what else can you really do to avoid buying high and selling low? That is if you sell at all. Not really the point of a long-term strategy I guess. You also collect some dividends on the way back up. Seems they can add up over time. Had to wait quite a few years for SPY to get back to the 150's from the 2000 high to 2007. But you collected something like $12/share in dividends from the 2002 bottom to the 2007 top. Just rambling. But also looking for a long-term investment strategy that makes some sense. Not a huge fan of buy and hold over the next 20-30 years. That's the most typical advice I hear. But boy I'm glad I didn't do that back in 2000 or 2007.