By Leonard Sloane

It's one of the first things new employees are asked to do: Enroll in a workplace retirement plan. Before doing so, though, they should ask themselves a few basic questions, which can help them make the most of a savings tool that has minted hundreds of thousands of millionaires.

Qualified retirement-savings plans like 401(k)s — and 403(b)s and 457(b)s in the public and nonprofit sectors — allow workers to save for retirement while deferring taxes. More than 65 million Americans have 401(k) accounts with total assets of $7.9 trillion, according to the Investment Company Institute.

Here are three questions newcomers to this group should ask:

How does vesting affect the company's match?

Your answer to this question can help you understand what you might give up if you leave the company before becoming fully vested.

More than 80% of companies that offer 401(k) plans make matching contributions for their workers, according to the Plan Sponsors Council of America. One common formula is a match of half of the first 6% of a worker's salary.

But you may not immediately own all of those matching contributions if your company has a vesting schedule, which links receipt of the funds to service time.

Some plans use graded vesting, under which ownership increases gradually over time — for example, by 20% a year. Others use cliff vesting, under which you receive no ownership until a specified date, such as three years of service, and then become fully vested.

You also become fully vested, regardless of service time, when you reach the plan's normal retirement age (typically age 65).

Depending on the vesting schedule, then, you could forfeit some or all of that money if you leave the company before becoming fully vested.

Is there an Roth 401(k)?

Most workplaces offer a traditional 401(k), which allows employees to make pretax contributions that reduce current taxable income. But more plans are adding or have a Roth 401(k) option, which is funded with after-tax dollars but allows qualified withdrawals in retirement to be tax-free.

A Roth 401(k) option "is particularly valuable to young people who are probably in a lower tax bracket now than they will be later in their careers," says Sarah Brenner, director of retirement education at Ed Slott & Co., a tax consulting firm in Rockville Centre, N.Y.

Beyond the years of tax-free growth you can get from Roth 401(k)s as a young worker, you won't have to deal down the line with the annual withdrawals on traditional 401(k)s, known as required minimum distributions, that can have an impact on your taxes in retirement.

If both options are available, you can usually split contributions between the two. This would give you the benefits of both tax scenarios during your working years and in retirement.

The contribution limit on employee contributions for 2026 is $24,500 in total, and usually rises a bit each year to account for inflation. Older employees may have options to make catch-up contributions.

What are the plan's annual fees?

Administrators of 401(k) plans charge an annual fee to cover investment, management and administrative expenses. While annual fees may appear small, the cumulative amount could be well into six figures and can significantly reduce long-term returns because investors lose not only the fee itself but also the growth that money could have generated.

Thus, the answer to this question can help you identify ways to reduce costs and potentially keep more of your long-term returns.

Annual plan fees often range from 0.25% to 1% of total assets in the account.

Your investment choices also have an impact on fees. If your assets are in index mutual funds, fees are usually lower than with actively managed funds.

If there are no or few low-fee funds offered by your 401(k) plan, an option is to contribute only enough to obtain a full company match and then contribute other savings to an IRA.

To find the answers to these and other questions you might have, start by reading the 401(k)'s summary plan description, which provides information in plain and understandable language. You can also contact the plan administrator — often a financial-services company like Vanguard or Fidelity — or your human-relations department.