If you want to save for retirement, using a Roth IRA can be the best decision you'll ever make. But you have to know all the Roth IRA rules to make the most of it. Here are the key Roth IRA rules, with updates to show you how they've changed in 2014.

Roth Rule 1: If you make too much money, you can't do a Roth.
The most important thing to know about the Roth is that the IRS doesn't allow some taxpayers to contribute to one at all. If you're considering a Roth for the 2013 tax year -- which you can still do until April 15, 2014 -- then you can't make more than $127,000 if you're a single filer or $188,000 if you're filing jointly, or else you won't be allowed to put any money into a Roth. Singles with income between $112,000 and $127,000 or joint filers with income between $178,000 and $188,000 can only contribute reduced amounts to a Roth.

If you're considering a Roth for the 2014 tax year, the Roth IRA rules for income limits above which contributions are completely prohibited are $129,000 for singles and $191,000 for joint filers. Beginning at $114,000 for singles and $181,000 for joint filers, you'll face reduced contribution limits.

Roth Rule 2: You can only contribute up to a certain amount to a Roth.
Roth contribution limits are indexed for inflation, but after rising in 2013, they're scheduled to stay the same in 2014. That means you can contribute up to $5,500 to a Roth IRA in 2013 and 2014, with those 50 or older entitled to an extra $1,000 catch-up contribution. Again, those limits apply to each tax year, so if you haven't contributed yet for 2013, you can still do so through mid-April.

Roth Rule 3: Distributions from your Roth IRA are tax-free -- usually.
The key benefit of the Roth IRA is that distributions are entirely tax-free, so long as you follow the rules. But those rules are complex, with different provisions covering your initial contribution versus the earnings from your Roth. Although penalties can apply to withdrawals before age 59 and a half or within the first five years you have your Roth, you can avoid them in certain circumstances, such as withdrawals for costs related to an IRS-recognized disability, first-time home costs, or higher-education expenses.

Roth Rule 4: Roths can last after you die -- if you're smart about naming beneficiaries.
Most people figure they'll use up all their savings before they die. But Roths offer an attractive feature in that they can let the heirs you name get tax-free treatment for an inherited Roth IRA. When you pick beneficiaries, keep in mind that if they want, they'll be able to take out money gradually, keeping the rest to grow tax-free throughout their lifetimes. That might make choosing a younger beneficiary for a Roth a smart move, as it lengthens the amount of time they can keep money in the inherited Roth.

Roth Rule 5: Want to convert your traditional IRA to a Roth? You can -- regardless of income.
One way to get around the income limits on Roth contributions is to convert a traditional IRA to a Roth. Before 2010, separate Roth-conversion income limits prevented some from doing Roth conversions. But since then, taxpayers at any income level can convert. You'll still have to include the amount of previously deductible contributions to the converted IRA as taxable income, but since Roth IRA income is tax-free, it might be worth paying tax now to save more later.

Find out why the Roth IRA rules!
Keeping up to date about Roth IRA rules will let you make the most of these great retirement tools and avoid the mistakes that many make with their retirement. For the absolute latest on Roth IRAs, this IRS website link will take you to all the detailed information you and your accountant will want to decide whether a Roth IRA is right for you.