It’s a trick question, of course. If you’re asking it, then it’s time to review your long-term investment strategy (or to come up with one, if you haven’t done so).

The bottom line is that trying to time the market is a loser’s game. Those who say they can do it are blowing hot air up your skirt. Sure, some people sell in time to avoid the worst of a downturn–and then they typically miss the rebound that inevitably follows.

If you’re investing for a goal that’s decades away, such as retirement, then the day-to-day fluctuations of the market are irrelevant noise. Even if you’re close to retirement age, you’re still going to need a hefty exposure to stocks to give you the growth you’ll need over time to offset inflation. You can’t expect gains without declines, though. They’re part of the deal.

If you really feel you need to do something, then get a second opinion on your current asset allocation–how your investments are divided among stocks, bonds and cash. You can get free advice from sites such as FutureAdvisor or look into low-cost options from Vanguard or Schwab, among others. Another option is to hire a fee-only planners who charge by the hour or who charge a retainer or a percentage of assets. The Financial Planning Association has tips on choosing a financial planner. Once you have a target asset allocation, you’ll have a map to follow regardless of what the market does.