Here’s a telling scenario: If you put $100,000 in stocks on July 1, 1994, and stayed fully invested for five years, your $100,000 grew into $341,722. But if you were out of stocks for just thirty days over that stretch—the thirty days when stocks had their biggest gains—your $100,000 turned into a disappointing $153,792. By staying in the market, you more than doubled your reward.