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 Retirement Redefined Around the country, attitudes about retirement are shifting. 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.