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? Retirement Traps to Avoid Beware of these traps that could upend your retirement. My Retirement Savings Estimate how long your retirement savings may last using various monthly cash flow rates.