NEW YORK -- Happy 30th birthday to the Individual Retirement Account.

Created by Congress in 1974, the IRA has become a useful tool for workers to save for retirement, especially those who don't have a company-sponsored plan.

Americans had an estimated $2.33 trillion in IRA accounts at end of 2002, according to the most recent figures from the Investment Company Institute trade group in Washington, D.C. That represented about one-fifth of total retirement savings of $10.15 trillion.

Although attention in recent years has focused on other savings vehicles such as the company-sponsored 401(k) retirement plans, there's still a place in many families' savings strategy for the traditional IRA and its younger cousin, the Roth IRA.

"IRA contributions, because of compounding over time, can add up to significant dollars to help ensure a comfortable retirement," said Anthony Luciano, vice president of retirement products at Fidelity Investments in Boston.

Technically, anybody can open an IRA. But workers who are covered by employer-sponsored retirement plans are not able to take a tax deduction for their annual contribution.

A worker who opens a traditional IRA can put up to $3,000 into the account this year; those 50 and older can invest an additional $500. Next year, the limit will rise to $4,000, with a $500 catch-up provision for older workers.

Workers who are not eligible for company-sponsored retirement plans -- about 40 percent of the work force -- get a double tax benefit. They get the tax deduction for their contribution, and earnings aren't taxed until the money is withdrawn for retirement starting at age 59 1/2.

While workers who have company plans can't deduct their annual IRA contributions, the money still grows tax-deferred until retirement.

Roth IRAs -- which were created in 1997 and named for William V. Roth Jr., the late Republican senator -- work a bit differently. They're funded with after-tax money, which means there's no deduction, but grow tax-free forever. And there are income limits for opening Roths -- $150,000 for couples and $95,000 for individuals.

The fact that Roths provide lifelong tax protection has made them increasingly popular, not only as savings accounts for workers with no company plans but also for workers who want to supplement company offerings, Fidelity's Luciano said.

"We see folks who contribute to their 401(k) up to the company's matching contribution, then use an IRA for other money because there are more investment options," he said. "Or they max their 401(k) and also fund an IRA."

Fidelity has a calculator on its Web site at www.fidelity.com to help people determine whether a traditional IRA or a Roth would be better for them.

Banks, savings banks, mutual fund companies and brokerages can help consumers set them up. And workers who didn't fund an account last year have until April 15 to make their 2003 contributions.

Ed Slott, an IRA specialist in Rockville Centre, N.Y., who wrote "The Retirement Savings Time Bomb," describes the Roth as "the greatest savings vehicle ever created" and said it should be especially attractive to young people.

"If you get into the habit of saving and put a few thousand into a Roth every year, before you know it you'll have a few hundred thousand -- all tax free," Slott said.

Workers also can use IRAs to stash the balances from their company-sponsored plans when they change jobs. Financial institutions can help savers open these "rollover" IRA accounts in a way that they don't jeopardize the tax-deferred status of their savings.

Dallas Salisbury, chief executive of the nonprofit Employee Benefit Research Institute in Washington, D.C., said IRAs had not been as popular as they might be because some savers were put off by the income limits on participation and the complexity of the rules governing the accounts.

The Bush administration has proposed replacing the IRAs with a tax-sheltered account that has no income limits, but it is unclear if the plan will be approved by Congress. The Retirement Savings Account, as proposed, would allow a worker to set aside up to $5,000 a year in after-tax money. Earnings and withdrawals would be tax-free starting at age 58.

"It would be easier to promote [such an account] because it could be advertised to everybody," Salisbury said. "That sparks participation across the income spectrum."