I know that withdrawals on earnings in a Roth IRA are non-taxable once the IRA is over five years old. If I fund a Roth IRA now, do I still need to wait five years before earnings withdrawals are tax-free, since I am 67 and already at retirement age? — Dan B.

Although 59 ½ is the age after which most people can withdraw Roth IRA earnings tax-free, no matter what your age, you must wait five years after opening a Roth to avoid those taxes. "Putting money in a Roth basically assumes you won't need that money for five years," says Keith Amburgey, a CFA and principal of Rutherford Asset Planning in Tampa, Fla. You can withdraw regular contributions (not conversions from a traditional IRA) at any time — just not the earnings on those contributions.

If you expect to need ready access to all your money, you may be better off contributing those funds to a traditional IRA, says Amburgey. But if you can afford to wait the five years, the Roth is a great choice. Reason: Unlike traditional IRAs, Roth IRAs aren't subject to required minimum distributions at age 70 ½. You'll no longer be able to contribute to the Roth past that age, but your assets can continue to grow tax-free for as long as you want — even if you decide to pass those assets to your heirs.

— Austin Kilham

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