An annuity

Immediate annuities allow you to hand over a chunk of your retirement savings to an insurance company in exchange for guaranteed monthly payments for the rest of your life. The costs and fees of some annuities can be high, and you generally won't be able to pass the money you use to purchase an annuity on to heirs. But you gain a predictable monthly income, even if you live past age 100 or the stock market takes another dive, as long as the insurance company stays in business. "With the insurance company annuity, the insurance company guarantees that the money will last the rest of your life no matter how long you live," says Steve Vernon, a fellow of the Society of Actuaries and author of "Money for Life: Turn Your IRA and 401(k) into a Lifetime Retirement Paycheck." "If you want that lifetime guarantee, you are going to have to trade off access to your money. With most annuities, once you give your money over to the insurance company, you can't get it back other than the monthly paycheck."

A pension

Workers fortunate enough to get a traditional pension through their jobs generally have a second guaranteed source of monthly retirement income. Most private-sector pension plans are insured by the PBGC, which guarantees pension benefits up to certain annual limits and will pay out benefits if your former employer goes out of business. However, workers with traditional pensions are increasingly being offered lump-sum pension payouts, which do not come with the same protections. If you don't manage a lump sum prudently or you live longer than you expected, you could end up spending that money too quickly.

Social Security

Social Security is your first line of defense against outliving your savings because these payments will continue for the rest of your life and are adjusted for inflation each year. Anyone who qualifies for Social Security will never completely run out of money, but could have to cut their standard of living to survive on their Social Security payment if they exhaust all other sources of income. Since this is the only guaranteed source of income most retirees have, it's a good idea to try to increase the amount you will get. Common strategies for boosting your Social Security payments include making sure you have at least 35 years of covered earnings, claiming spousal payments, and delaying claiming up until age 70. "Get your [online] Social Security statement from the Social Security Administration and then go through that information and use it to decide when to claim Social Security," advises Troy Von Haefen, a certified financial planner for Von Haefen Financial Management in Nashville.