It looks like the U.S. stock market will finally get something that happens, on average, about once a year: a 10+% percent drop—the definition of a market correction. The last time this happened was a whopper—the Great Recession drop that caused U.S. stocks to drop more than 50%–so most people today probably think corrections are catastrophic. They aren’t. More typically, they last anywhere from 20 trading days (the 1997 correction, down 10.8%) to 104 days (the 2002-2003 correction, down 14.7%). Corrections are unnerving, but they’re a healthy part of the economy—for a couple of reasons.