If you are an investor, which i assume you are based on the tone of your comment, why would you want to buy on the way down? Wouldn't you be better off to buy on the way up (which could be several years hence)? If you are a trader, you could take advantage of rallies to buy and book some quick profits, but don't lose site of the fact that the market should have quite far to fall yet, and any buying will be counter to the main trend, and that always entails more risk than going with the trend. Next stop on the way down for the S&P will be near 1375. How soon we get there, nobody knows. And of course there will be some rallies on the way down fueled in part by short covering and by those who are trying to guess the bottom or see the current levels incorrectly as "buying" opportunities.
one thing I have learned in the past 20 years that these large threshold numbers are like magnets attracting large and small traders to break through. If it did not happen today it will happen tomorrow, or Thursday. It has no real significance but it is psychological like flame attracting the moths.