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 Should You Ever Retire? A growing number of Americans are pushing back the age at which they plan to retire. Or deciding not to retire at all. Volunteering in Retirement For many, retirement includes contributing their time and talents to an organization in need. A Look at Systematic Withdrawals This calculator may help you estimate how long funds may last given regular withdrawals.