Period certain income annuities have set income terms, making them useful for helping to fund early retirement or prefund a loan or large life insurance policy. Immediate income annuities with a lifetime payout are popular for a good reason. By providing immediate monthly income that’s guaranteed for life, they help assure a worry-free retirement. But you don’t have to choose the lifetime option. Instead, you may want to choose a set income term, from five to 20 years. Sometimes it makes perfect sense to choose a period certain income annuity.