So what’s an investor to do?

That’s where the similarities end, however. Investment companies offering these products choose different initial mixes of stocks and bonds as well as different “glide paths,” or rates at which the mix is adjusted. On average, target date strategies for 2020 had 43% of their portfolios invested in stocks, but one fund had 55% in stocks while another had just 8%, Acheson says.

The types of investments differ, as well. For example, some funds that are more conservative with their stock allocation take more risks with their bonds, choosing corporate bonds or even high-yield “junk” bonds over U.S. Treasurys and other government debt. Those riskier bonds offer better returns in good times but often get trounced in extreme downturns, when investors flee to the safety of government bonds.

On top of all that, investment companies tinker with their formulas, so the strategy in place when you initially invested might change by the time you retire.

Understanding how your target date works requires time and research. Your 401(k) provider or brokerage will be able to provide you with information, including how the investment’s glide path works, its expense ratios and how those compare to industry averages. Then you have to decide if you’re comfortable with its approach, given the expected risks and returns.

If you decide you’re not happy with your current choice, you have options. If you’re in a workplace retirement plan, you might choose a different date (such as the 2015 fund if you think the 2020 option is too risky, or Target Date 2025 if you’re willing to take more risk), though you probably can’t switch target date providers since most 401(k)s only offer one. If your money is in an IRA or taxable account, you could switch providers as well as target dates.

Another possibility is to craft your own portfolio. Consider consulting a fee-only, fiduciary advisor — one who’s committed to putting your best interests first — for help.

Getting good advice is something you should do anyway before you retire, because many retirement decisions are irreversible and mistakes can make your life a lot less comfortable. Also, our ability to avoid financial errors tends to decline starting in our 50s, even though our confidence in those abilities remains high. Working with a trusted advisor can help us avoid blind spots that could be costly.

All of this work is the exact opposite of the hands-off-the-wheel approach you probably wanted when you chose a target date investment. But staying hands-off — or making changes without professional advice — could mean losses that drive your retirement into a ditch.

JEFF ROBERSON — THE ASSOCIATED PRESS A woman walks into a closing Gordmans store, last week in St. Charles, Mo. Stage Stores, which owns Gordmans, is closing all its stores and has filed for Chapter 11bankruptcy.