If you're already retired, your choices are harder. You'll need to either lower your standard of living, downsize to reduce fixed expenses or take in a roommate to ensure that your savings last.
"The one thing we all control is our spending," Brown said. "We all need to realize that what we do today could lead to reduced spending and downsizing later in life."
Be sure, too, that you don't get too conservative too soon with your asset allocation. Unless you are independently wealthy, said Brown, stocks should still comprise 50 percent or more of your portfolio to offset the effects of inflation and generate the income you need.
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Annuities — insurance products that pay out lifetime income in exchange for a lump-sum payment or series of payments — have long been used to create guaranteed retirement income, but with interest rates so low, it's worth considering alternatives, Brown said.
"If you can find a low-cost, no-commission fixed annuity with no escape fee, then annuitizing maybe 15 percent of a portfolio can be beneficial," he said, noting dollar-cost averaging over the next 24 months — or buying smaller increments over a longer period of time — might work best, given the interest-rate environment.
To generate stable income, some financial advisors recommend retirees own mostly dividend-paying stocks and laddered bonds, in which the bonds' maturity dates are evenly spaced to minimize interest-rate risk and increase liquidity.
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But Horowitz at Evensky & Katz favors a different approach.
"It doesn't make sense to rely on dividend stocks and bonds, because your income rises and falls depending on their performance," he said. "It also forces you to buy only dividend stocks and certain bonds to meet your income threshold. You may be forced to buy higher-yielding junk bonds or stocks you wouldn't otherwise wish to own."