18 Years Worth of Days The average retirement lasts for 18 years. Are you prepared to fill that many days? Share | Have A Question About This Topic? Address Thank you! Oops! Related Contents Tuning Your Social Security Benefit When should you take your Social Security benefit? 9 Facts About Retirement Regardless of how you approach retirement, there are some things about it that might surprise you. Retirement Plan Distributions There are a number of ways to withdraw money from a qualified retirement plan.