Coins falling from above.

For years most investors largely ignored the fees they paid to invest. And it was easy to do because they look so small—just 1 percent or less of your portfolio.

But today more investors are catching on to the benefits of low fees, with many shifting their savings to less expensive options, such as index funds. More than $450 billion was stashed in index funds last year, according to Morningstar, the fund data firm.

That trend has sparked a price war among major fund companies to reduce investing fees. Among the latest cost-cutting moves, Fidelity has launched no-fee index funds. Vanguard, Schwab, and Fidelity also recently expanded their menus of exchange-traded funds (ETFs) that can be bought and sold without a transaction fee.

The impact of trimming your investing costs might not seem that important, but it could make or break your retirement success, says John Scott, director of the retirement savings project for The Pew Charitable Trusts.

As Pew’s free online calculator shows, a 20-something investor who saves in funds that charge low annual fees over 40 years will retire with $300,000 more than someone with the same portfolio who is charged higher fees.

Still, not all investors are taking advantage of lower costs. A recent Consumer Reports survey found that 4 in 10 investors weren’t sure how much they paid in fees. And among those who knew the costs, many said they were unhappy with the amounts being charged. 

If you haven’t reviewed your portfolio’s fees lately, or if you’re a beginning investor, it’s time to figure out what you’re paying—and whether you’re paying too much. “It’s never been easier to build a low-cost investing strategy,” says Rick Ferri, a financial adviser in Georgetown, Texas.

To find the right low-cost options, follow these five guidelines:

Get Control of Management Fees

It’s a wonky-sounding financial term, but your fund’s expense ratio is a key number to know. This is the annual fee that is charged by mutual funds and ETFs for investment management and operating expenses, which is calculated as a percentage of assets. This cost is deducted from your investment return.

More on Investment Fees

The average annual expense ratio these days is 0.52 percent, according to Morningstar, which means that someone with $10,000 invested would pay $52. But there’s a wide range. Some mutual funds charge 1 percent or more, and very low-cost index funds and ETFs charge just 0.10 percent or less.

You can check to see whether your fund or ETF’s expense ratio is high or low by plugging it into FINRA’s free fund analyzer tool.

If possible, stick with funds that charge less than 0.20 percent, such as broad index funds, Ferri says. If you are saving in a company-sponsored retirement plan, such as a 401(k), look for funds with the lowest expense ratios. (For more advice on 401(k) fees, see our article here.)

Say No to Sales Charges

A generation ago it was common to have to pay a fee, once as high as 8.5 percent, to buy and sell investments. Today it’s easy to avoid these commission costs, especially if you work with an online brokerage, because most offer a wide array of no-transaction-fee mutual funds and ETFs.

But if you’re working with a broker, be wary—you may still get a recommendation for a so-called A-share mutual fund, which will have the letter A at the end of its name. These funds typically charge an upfront sales load of 2 to 4 percent, and the expense ratio can be 10 times higher than a low-cost index fund, according to Morningstar. If you want help from a financial expert, you have more cost-efficient choices, as we explain next.

Pay Only for Advice You Need

Many financial advisers levy an annual charge of 1 percent of your assets to manage your portfolio, as well as provide financial advice. (That’s in addition to fund expense ratios.) Typically you must have an sizeable investment portfolio—often $250,000 or more.

But there are cheaper, more accessible alternatives. So-called robo-advisers, such as Betterment and Wealthfront, charge just 0.25 percent to oversee a portfolio of low-cost ETFs for you that are based on your age and appetite for risk. These computer-driven services automatically rebalance your portfolio to keep the right mix of stocks and bonds. You can get started with $500 or less.

You can pay even less for professional portfolio help by choosing a low-cost target-date retirement fund, says Allan Roth, a financial adviser in Colorado Springs, Colo. These funds provide a diversified mix of stocks and bonds that gradually shift to become more conservative as you approach your desired retirement date.

If you want personalized advice, consider hiring a fee-only certified financial planner—many are are available for an hourly fee or a flat fee. Use the search tool on the websites of Garrett Planning Network or the National Association of Personal Financial Advisors. The XY Planning Network offers advisers that charge an annual retainer. (For more tips on choosing an adviser, see this article.)

Avoid Firms with Add-On Fees

You can save money by sticking with major online brokerages, which don’t typically charge the account maintenance fees that are common at full-service (sometimes called traditional) brokerages.

For instance, Edward Jones charges an annual account fee of $40 for one IRA, and $20 for each additional IRA account. Morgan Stanley charges an annual account maintenance fee of $175 that is cut to $150 if you agree to e-delivery of your statements; an additional IRA account maintenance fee ranges from $50 to $100. By contrast, Schwab and TD Ameritrade charge no account maintenance fees.

Be a Buy-and-Hold Investor

The ease and low cost of online trading often tempts investors to buy and sell more frequently in an effort to outguess the market, says Meir Statman, a professor of finance at Santa Clara University in California, who specializes in behavioral investing.

That kind of strategy is bound to undermine the benefits of your low-fee portfolio because the average investor is unlikely to outmaneuver investment pros, Statman says. You may also be tempted to chase high-flying, high-cost investments at just the wrong time.

Still, you do have a key advantage—unlike investment pros seeking short-term profits, you can afford to be patient. Following a buy-and-hold approach tends to produce bigger account balances over the long term, studies show (PDF).

“As boring as it sounds, a buy-and-hold strategy is how you avoid letting your emotions get in the way of your long-term goals,” Statman says. “And you are more likely to achieve them.” That’s especially true if you keep your fees low.