What's the risk that the IRS will start taxing Roth IRA withdrawals? — Kipp E., Alexandria, Va.

It's low. There's no discussion in Washington of taxing them. And even if Congress did tinker with Roth IRAs someday — perhaps taxing withdrawals or eliminating Roths altogether — such changes probably wouldn't affect money already invested, say tax experts. "There would certainly be an uproar," says Tax Policy Center co-director Eric Toder.

If you're still worried about this theoretical risk, remember that your alternatives, such as pretax contributions to a traditional IRA or 401(k), carry risks too: Tax rates could be higher when you make withdrawals. To hedge your bets, it's good to keep assets in accounts with different types of tax treatments.

—Kate Ashford

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