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? Related Content Avoiding Cognitive Decline Try these activities to keep your brain sharp. Money that Buys Good Health is Never Ill Spent It's important to make sure your retirement strategy anticipates health-care expenses. Social Security: Maximizing Benefits There are other ways to maximize Social Security benefits, in addition to waiting to claim them.