There are plenty of aspects of retirement to worry about -- health issues, feeling bored, and lacking company once you're no longer going to an office every day. But if there's one specific worry that can be very hard to shake, it's the fear of running out of money. A good 71% of working Americans say they expect to be reluctant to spend their retirement savings once their careers end, according to a recent Allianz survey. How to avoid running out of money too soonIf a fear of depleting your retirement savings in your lifetime is causing you to underspend, it's important to address it rather than continue to deny yourself access to the money you worked hard to accumulate. First, come up with a safe withdrawal rate based on your retirement timeline and investment mix.