The rules for determining the source of money coming out of a Roth work in the taxpayer’s favor. The first money out is considered contributed amounts, so it’s tax- and penalty-free. Once contributions are depleted, you dip into converted amounts (if any). This money is tax- and penalty-free for owners 59 1/2 and older or younger ones who have had the converted amount in a Roth for more than five years. Only after you have cashed out all converted amounts do you get to the earnings. Once the account owner is 59 1/2 and has had one Roth for at least five years, earnings, too, can be withdrawn tax- and penalty-free.

The ability to tap money in a Roth IRA without penalty before age 59 1/2 allows for flexibility to use the Roth IRA for other purposes. For example, the account could be used as a fallback for college savings.

Once you reach retirement, having a pot of tax-free income to draw upon may allow you to lower your tax bill. Roth money doesn’t count in the calculation for taxing Social Security benefits, for example, or in the calculation for the new tax on investment income.

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Part 7 of 10 Things You Must Know About Roth Accounts

If you make a conversion, you must wait five years or until you reach age 59 1/2, whichever comes first, before you can withdraw the converted amount free of the 10% penalty. Each conversion has its own five-year holding period. So if a young account owner does one conversion in 2013 and a second conversion in 2014, the amount from the first conversion can be withdrawn penalty-free starting in 2018 and the amount from the second starting in 2019.

Earnings on a converted amount can be withdrawn tax- and penalty-free after the owner reaches age 59 1/2, as long as he or she has had any Roth IRA opened at least five years.

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Part 6 of 10 Things You Must Know About Roth Accounts

Because there’s no tax deduction for Roth contributions, you can retrieve that money at any time free of taxes and penalties, regardless of age.

But for earnings to be tax- and penalty-free, you have to pass a couple of tests. First, you must be 59 1/2 or older. You will get hit with a 10% early-withdrawal penalty and taxes if you take out earnings before you hit age 59 1/2. And you must have had one Roth open for at least five years. If you are 58 and opening your first Roth IRA in 2013, you can tap earnings penalty-free at age 59 1/2, but you won’t be able to tap earnings tax-free until 2018.

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Look at the big picture if you plan a conversion. The added taxable income could boost you into a higher tax bracket. A big jump in income could trigger other taxes, too, such as the new 3.8% surtax on net investment income. For Medicare beneficiaries, a rise in adjusted gross income could result in premium surcharges for Part B and Part D.

A series of small conversions over several years could keep the tax bill in check. For instance, you may want to convert just enough to take you to the top of your current tax bracket.

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Another route to tax-free earnings inside a Roth is to convert traditional IRA money to a Roth. In the year you convert, you must pay tax on the full amount shifted into the Roth. That’s the price you pay to buy tax freedom for future earnings. (If you have made nondeductible contributions to your traditional IRA, a portion of your conversion will be tax-free.)

If you expect your tax rate to be the same or higher in the future, converting could make sense; if you expect your future tax rate to be lower, it might not.

You’ll want to pay the tax owed on a conversion with money outside of the IRA. Drawing money from the IRA to pay the tax will result in an additional tax bill, and a penalty if you’re under age 59 1/2.

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Part 3 of 10 Things You Must Know About Roth Accounts

Many companies have added a Roth option to their 401(k) plans. After-tax money goes into the Roth, so you won’t see the immediate tax savings you get from contributing pretax money to a traditional plan. But your money will grow tax-free. (Any employer match will go into a traditional 401(k) account.)

For 2013 and 2014, you can stash up to $17,500 a year, plus an extra $5,500 a year if you’re 50 or older, into a 401(k). Contributions must be made by December 31 to count for the current tax year, and the limit applies to the total of your traditional and Roth 401(k) contributions. A Roth 401(k) is a good option if your earnings are too high to contribute to a Roth IRA.

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To be able to contribute to a Roth, you must have earned income. And unlike traditional IRAs, if you’re still working after age 70 1/2, you can keep contributing.

In 2013 and 2014, you can stash up to $5,500 in a Roth IRA and an extra $1,000 if you’re 50 or older.

But higher-income taxpayers are barred from contributing to a Roth IRA. For 2013, the ability to contribute to a Roth phases out if your adjusted gross income is between $178,000 and $188,000 for joint filers and between $112,000 and $127,000 for single filers. Those thresholds go up for 2014: $181,000 to $191,000 for joint filers and $114,000 to $129,000 for single filers.

You can make a 2013 Roth IRA contribution as late as April 15, 2014. You can contribute to both Roth and traditional IRAs, but the total cannot exceed the annual limit.

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