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 Social Security: By the Numbers Here are five facts about Social Security that might surprise you. Systematic Withdrawals in Retirement Taking regular, periodic withdrawals during retirement can be quite problematic. Retirement Plan Distributions There are a number of ways to withdraw money from a qualified retirement plan.