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 Long-Term-Care Needs Determine your potential long-term care needs and how long your current assets might last. Systematic Withdrawals in Retirement Taking regular, periodic withdrawals during retirement can be quite problematic. Self-Employed Retirement Plans Estimate the maximum contribution amount for a Self-Employed 401(k), SIMPLE IRA, or SEP.