 Once you know what that is and when it's likely to occur, synthesize your portfolio in as low cost and broadly diversified manner as possible to give you what is believed to be the highest probability of success. There are all sorts of unknowns. There is no perfect strategy. There is no way of knowing in advance which things will perform best. So you make no big bets in any one spot, hoping that that will help alleviate any massive blow up over a lifetime of investing.