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One of the most common misconceptions I hear about Social Security is that it makes no sense to work in your later years—and keep forking over payroll taxes—because your benefits won’t rise.

For full-time workers, this is absolutely not true. Social Security uses very favorable rules for measuring wages for people age 60 and older who are still working. And older workers are a big and growing army: More than 8.2 million persons age 65 or older were in the labor force last month, up from 4.7 million 10 years earlier, according to the U.S. Bureau of Labor Statistics.

Of course, one of the main reasons people are staying on the job is because they need the money. Their retirement prospects may be bleak to boot. So understanding these Social Security rules is more important than ever.

Social Security bases your benefits on the top 35 years of your covered earnings. As used here, “covered” means wages on which you’ve paid FICA (Federal Insurance Contribution Act) taxes. There is an annual cap on wages subject to these taxes, but it goes up each year to reflect the past year’s increase in national wages. In 2015, the cap is $118,500.

Each year, Social Security indexes your wage earnings, adjusting them to reflect the impact of wage inflation. It uses these indexed wage amounts to determine your top 35 years of earnings.

This way, people get fair credit for all of their past earnings years. Otherwise, a 66-year-old who earned most of his wages 30 years ago would receive less in benefits than a 66-year-old whose earnings occurred in more recent years.

Wage indexing stops at age 60. This is a big deal. The reasons aren’t important here—what is important is that your post-60 earnings are not indexed and thus flow directly into your earnings record in their unadjusted, or nominal, form.

Because wages have increased in this country nearly every year since 1950, the odds are very good that someone who keeps working full-time past age 60 will earn enough money to represent a new “top 35 year.”

This is automatically the case for high earners whose wages exceed the annual cap. As the cap rises, so will the amount of their covered earnings, automatically becoming a new top-35 year. But even lower-earning individuals face good odds of having their post-60 earnings become new top-35 years.

When this happens, Social Security will automatically recompute not only your retirement benefits but the benefits of anyone else—a present or former spouse, young children, and even your parents—that are linked to your earnings record. And it will do this for every year in which your unadjusted earnings are large enough to become one of your top 35 earnings years.

Having said this, I share the frustration that many older workers express for continuing to fork over payroll taxes even after they’ve reached their maximum Social Security benefits. Paying something for nothing is no fun, and in this case it’s not right.

My solution, which maybe has just a constituency of me, would be to cut payroll taxes for workers who are at least 70 years old—and to cut them for their employers as well. This will still bring new taxes into Social Security, but it also will recognize the reality that these workers largely have already paid for their Social Security benefits.

Giving their employers a break will also create needed incentives to encourage hiring and retaining older workers. Right now, many employers balk at doing do, citing higher health care and perhaps retraining costs for older employees. Yet the need for this and other “aging America” changes is becoming clearer with each passing day.

Philip Moeller is an expert on retirement, aging, and health, and co-author of “Get What’s Yours: The Secrets to Maxing Out Your Social Security,” Reach him at moeller.philip@gmail.com or @PhilMoeller on Twitter.