The Power of Tax-Deferred Growth Why are 401(k) plans, annuities, and IRAs so popular? Share | Related Content 18 Years Worth of Days The average retirement lasts for 18 years. Are you prepared to fill that many days? When Should You Take Social Security Monthly Social Security payments differ substantially depending on when you start receiving benefits. Retirement Plan Distributions There are a number of ways to withdraw money from a qualified retirement plan.