In a secular bear market, like 1966-1982 bear or the secular bear market that began in March of 2000, investors primary goal is to manage risk and protect capital.
It's kind of funny that after the 2008 collapse everybody has been mouthing those words. But, I've been saying that for ten years now. This is a secular bear market and you have to be very much aware of lots of volatility – strong rallies up, strong collapses down. If history is your guide, than you should expect to see five major swings from the bottom to the top and back before this whole mess is over.
Right now we're probably on the third leg. You had the initial crash in 2000-02/03, strong rally, big crash in 2008-09, big rally and if history holds true we should see one more major correction before the secular bear market is over.
History also tells us that, typically speaking, the middle collapse is the worst of all. Again, understanding the broader historical patterns doesn't change what we do day to day, but it very much colors our longer term thinking.