18 Years Worth of Days The average retirement lasts for 18 years. Are you prepared to fill that many days? Share | Related Content How to Retire Early Retiring early sounds like a dream come true, but it’s important to take a look at the cold, hard facts. What Is a Roth 401(k)? Roth 401(k) plans combine features of traditional 401(k) plans with those of a Roth IRA. My Retirement Savings Estimate how long your retirement savings may last using various monthly cash flow rates.