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? What Is a Roth 401(k)? Roth 401(k) plans combine features of traditional 401(k) plans with those of a Roth IRA. Retirement Plan Distributions There are a number of ways to withdraw money from a qualified retirement plan.