traineeinvestor
Thinks s/he gets paid by the post
How can you take advantage of it? I you mean buying at the bottom one never knows when it is going to stop, and if you were invested before, then all of your funds are in the market when it dropped, right?
I agree that no one can pick either the market top or the market bottom with any great degree of certainty, but when valuations start looking stretched I either reduce exposure to equties or stop buying new ones (or both). When they look cheaper (below long term averages), I do the reverse. Of course prices can always go lower (higher), but if my time horizon is long enough, then I can be confident that I can ride out any further downturn.
At the moment, I'm still accumulating assets. Once I retire, I will still be able to take advantage of price declines by selling bonds and/or spending some of the 2-3 years (?) cash set aside for near term living costs. If I'm feeling really ambitious, I could even take out a mortgage against one of my properties to generate some cash for new investments (although I suspect my wife may have more than a few words to say about that).
And yes, I accept that this may be viewed as aggressive and risky for a retiree. If things go really wrong, there is always the possibilty of getting job.