But this is exactly what you shouldn't do. "Studies have shown that investors who less actively monitor and trade in their retirement accounts perform better than those who do," Johnson said. "The best strategy for young people is to 'set it and forget it.'" In other words, they should make regular contributions to a low-cost index fund that tracks a market index such as the S&P 500 or target-date fund in a retirement account and stay the course.
Don't set and forget entirely, though. Increase contributions as your income rises to ensure that saving 10 percent to 15 percent of your wages annually, as experts recommend.