It's been around for more than a decade. But if you don't use it, you lose it -- and the savings are too good to miss.

The Roth IRA first came into being back in 1998, and plenty of investors have taken advantage of its unique characteristics to help them save for retirement. Although the amount of money in traditional IRA and 401(k) plans still dwarfs what people have in Roth IRAs, Roths enjoy something those other plans can't offer: completely tax-free growth.

A novel concept
Back then, the whole idea behind the Roth IRA was completely new. There were plenty of different ways the tax laws allowed people to save for retirement, but they were all based on the concept of deferred compensation. You set money aside during one year for use in a later year. For tax purposes, the laws followed that concept, too. The benefit was that you wouldn't have to pay tax in the year you set aside the money; instead, you deferred the tax until the year you actually used it.

There's no denying that tax deferral is a valuable benefit in retirement saving. The Roth IRA, however, went one step better by providing tax elimination. Granted, you don't get the valuable tax deduction that so many IRA and 401(k) participants enjoy. But by giving up that one-time benefit, you earn a lifetime exemption from taxes on that money.

Still going strong
After more than 10 years, investors are starting to see some of the benefits of tax-free treatment for Roth IRAs. Back in 1998, you could contribute only $2,000 a year to your Roth IRA. But as you can see below, 12 years of investment could have turned that $2,000 into a lot more.

Stock

$2,000 in 1998
Is Now Worth

Potential Tax Avoided
Over Traditional IRA

Southern Copper (NYSE: SCCO)

$50,739

$17,759

Amazon.com (Nasdaq: AMZN)

$41,141

$14,399

Panera Bread (Nasdaq: PNRA)

$36,408

$12,743

Guess? (NYSE: GES)

$29,317

$10,261

Cal-Maine Foods (Nasdaq: CALM)

$24,187

$8,466

Dish Network (Nasdaq: DISH)

$19,559

$6,845

Apache (NYSE: APA)

$15,397

$5,389

Source: Yahoo! Finance. Returns as of March 3. Assumes 35% tax on traditional IRA withdrawals.

And that's just the tip of the iceberg. Unlike traditional IRAs, Roth IRAs never force you to start taking withdrawals, no matter how old you are. That means that it's entirely up to you how much you take -- and how much you leave to grow inside your Roth IRA for decades to come.

Double your fun
If you haven't made a Roth IRA contribution for 2009 yet, you only have until Apr. 15 to get it done. For both 2009 and 2010, you can contribute up to $5,000 -- more than double the original amount in 1998 -- to a Roth. In subsequent years, that limit will be indexed for inflation, further multiplying the potential savings. And if you're 50 or older, you can add another $1,000 on top of that limit.

So don't let another year go by without capitalizing on a great way to save toward retirement. In just a decade, the Roth IRA has revolutionized retirement savings -- and with everything the Roth has going for it, you can't afford to lose another opportunity.

Learn more about investing for retirement from the Fool's Rule Your Retirement service. A 30-day trial is absolutely free and gives you access to everything we've got to help you.

This article was originally published on April 9, 2008. It has been updated by Dan Caplinger, who doesn't own shares of the companies mentioned. Amazon.com is a Motley Fool Stock Advisor selection. Try any of our Foolish newsletters today, free for 30 days. The Fool's disclosure policy has been around for years, and it ain't going anywhere.