1. Scale Back Spending

Which to buy first: top-of-the-line golf clubs, a speedboat or a vacation home in Key West? It's a tough choice, but without careful planning "none of the above" might have to be the answer. "Some people see retirement as a green light to do every bit of spending that they never did while they were working," says Gary Schatsky, a fee-only certified financial planner based in New York City. "But to make retirement last, you need to spend less, spend less, spend less."

That's not to say you shouldn't enjoy your work-free days -- just resist the urge to treat the contents of your accounts like mad money. Withdrawing too much, too soon leaves you with lower balances and less potential to earn retirement-sustaining returns. And forget about that cushy 15% income tax rate most retirees are eligible for, warns Schatsky. As soon as you have more than $63,700 in retirement income, the tax rate skyrockets to 25%.

Impact: To you, nothing says "retired" like a fast, wind-in-your-hair drive to the beach in a swanky convertible. Forgo the brand-new 2007 BMW 3-Series (MSRP $49,100) in favor of one that's coming off a two-year lease ($37,300). You'll save 24%, and leave $11,800 of your retirement stash untouched. As part of a $250,000 portfolio growing tax free and earning 8% annually, that's an extra $29,138 (including $17,338 in earnings) over five years.