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If you're like many people, you've put considerable time and effort into socking away money for retirement. But you've probably put less thought into how to spend the money in a way that will make it last, leaving you with a potential disaster.

A perfect storm has foisted this challenge on us. People are living longer. Fewer people have pensions and the 401k plans that more have come to rely on likely were decimated n the recent downturn. Further, assets in savings accounts may actually be losing value, thanks to short-term interest rates that are lower than the inflation rate. And the future of Social Security seems iffy.

There are steps you can take to make your money last. Spending less and working longer will help, of course. But even then you can't know how long you're going to live. All you have are the odds: For a married couple at age 65, there's a 58% chance one person will live to 90; a 50% chance one will live to 92; and a 25% chance one will live to 97.

William Wixon, the owner of Wixon Advisors, tells his Minnesota clients to plan for a retirement of 30 to 35 years. How can they make their money last that long, or longer? Let's say you're 65 years old, you want to retire now, and you expect to need $100,000 annual income in retirement. You'll need to adjust that $100,000 to rise with inflation because, as Wixon says, "What's a loaf of bread going to cost in 30 years? Maybe nine bucks." Here are some options for you, with pros and cons.

Savings accounts

If you have a Depression-era mentality, put your nest egg in savings accounts and certificates of deposit with no more than the FDIC-insured limit of $250,000 in any one bank. It's safe and will be there for you no matter what the markets do.

Unfortunately, inflation may erode the value of such low-risk investments over time after inflation, and they are unlikely to generate much income. If you have a pot of money for getting you through your golden years, the most you should withdraw annually over a 30-year period is 5% (some people say 4%). With current savings interest rates of around 2%, you would need to start with $5 million to generate $100,000 a year in income. And that doesn't even account for inflation pressures on your annual withdrawal, as the buying power of your $100,000 decreases.

A balanced portfolio

If you don't happen to have $5 million lying around, you'll need to accept more risk to have any chance of generating that $100,000 a year you desire. One alternative is to put money in a diversified portfolio of stocks, bonds and real estate that pays dividends. If you start with $3 million and the market performs as it has over the past 70 years, you should be in good shape. But if the market lags or companies cut their dividends, your money might not last.

A recent white paper from Vanguard Group discusses making systematic, fixed, inflation-adjusted withdrawals from a balanced mutual fund of stocks and bonds. Adjusting your withdrawals based on the inflation rate might reduce the risk that you'll run out of money, but it won't eliminate it entirely.

Immediate annuities

With an immediate annuity, you put money in an insurance contract that usually pays a fixed rate of return (much like a certificate of deposit) and start receiving those payments within a year. How much income your lump sum will generate depends largely on how much you invest, your gender and age at the time you buy the annuity, and the prevailing interest rate environment (currently unfavorable to annuity buyers). A 65-year-old woman living in Illinois would need to plunk down about $1.5 million to generate $100,000 in inflation-adjusted annual payments for life.

It pays to comparison-shop for immediate annuities, especially among low-cost vendors like Vanguard and TIAA-CREF. Also consider tailoring the annuity to your needs --by arranging for payments to continue until both spouses pass away, for example.

One downside is that an immediate annuity ties up your money, so you won't have access to it in an emergency or to pass on as an inheritance if you get hit by a bus the day after you buy it. It also locks you into the interest-rate environment at the time of purchase. You can get around this by buying separate annuities in chunks over several years. To lock in real, after-inflation income, opt for an inflation-adjustment rider, but understand that it will cut into how much you'll receive each month.

Deferred annuities

With a deferred annuity, you pay now and hope to accumulate assets through either a variable product that invests in equity mutual funds or a fixed product that offers bond-like returns. How much you'll receive each month when you start to draw down your annuity will then depend on how your variable or fixed investments do over time.

Putting aside money this way may encourage you to save for retirement. But it may also come at the cost of hefty surrender fees or penalties if you decide you need to tap your savings prematurely.

Another reason to consider deferred annuities is that they enable you to continue saving in tax-deferred plans after you've maxed out your 401k and IRA. You will still have to pay taxes as you withdraw the money, though. And unlike an immediate annuity, if your deferred annuity has a balance when you die, it goes to your heirs.

The downside of deferred annuities include lockups and often exorbitant fees. You pay an average of 2.15% a year, according to one study, and you could pay up to 4% annually in fees. Unless the tax deferral is truly important, you might be better off investing in tax-efficient mutual funds or exchange-traded funds until you need the money, and then converting them into an immediate annuity. It's not risk-free, but it may save you a lot of money in the long run.

Guaranteed lifetime withdrawal benefits

Many deferred variable annuities buyers avoid the risk of outliving their savings by paying for guarantees that payments will last until they die. That's one way to guarantee your $100,000 annually lifetime income will continue (as long as the insurer remains in business).

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Unfortunately, $100,000 will not buy in 20 years what it does today. Cost-of-living adjustments come at a price of about 1% per year with GLWBs. That's on top of the price of the annuity and the underlying investments. Add them up, and the costs could come to a pricey 5% in all. Further, if you tap your money for an emergency, you risk blowing up the guarantee. One more caution: If you still want the product, prepare to shop with professional assistance, because insurance companies seem to go out of their way to make GLWBs confusing.

Reverse mortgages

If, despite your planning, you still come up short, a reverse mortgage might help you make ends meet. It is essentially a specialized home equity loan available to people 62 and older that lets you borrow against your equity and collect the money as a lump sum or as regular payments for as long as you live.

The advantage to this arrangement is this lets you tap the equity in your home without having to meet any income guidelines or make immediate payments, as you would with a regular home equity loan. Yet the costs of reverse mortgage are high, and when you're gone your heirs might have to give up the family home to pay back the loan.

If your home loses value, any shortfall against the loan is the Federal Housing Administration's problem. But remember: You still have to pay taxes, insurance and upkeep on your house. And a reverse mortgage won't provide $100,000 for long. The maximum loan you can get in most cases is some percentage of $625,000, based on your age.