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. Share | Related Content 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? Should You Borrow from Your 401(k)? Does it make sense to borrow from my 401(k) to pay off debt or to make a major purchase? My Retirement Savings Estimate how long your retirement savings may last using various monthly cash flow rates.