 The advantage of such an annuity is that the annuitant has a guaranteed income for life, whereas if the retiree were instead to withdraw money regularly from the retirement account (income drawdown), he/she might run out of money before death, or alternatively not have as much to spend while alive as could have been possible with an annuity purchase.Another common use for an income annuity is to pay recurring expenses, such as assisted living expenses, mortgage or insurance premiums.The disadvantage of such an annuity is that the election is irrevocable and, because of inflation, a guaranteed income for life is not the same thing as guaranteeing a comfortable income for life.