18 Years’ Worth of Days The average retirement lasts for 18 years, with many lasting even longer. Will you fill your post-retirement days with purpose? Share | Related Content Retirement Redefined Around the country, attitudes about retirement are shifting. Retirement Income and the Traditional Portfolio Experiencing negative returns early in retirement can potentially undermine the sustainability of your assets. My Retirement Savings Estimate how long your retirement savings may last using various monthly cash flow rates.