Have an F.S.A.? You May Be Able to Carry Over More Money in 2022.

With annual open enrollment underway at many employers, workers should log on to their accounts or check with their employer to see how much money is available and decide whether to tweak their paycheck deductions for next year, Ms. Myers said.

“Employees need to know their balances,” she said.

Employers have generally said they are seeking to hold the line on increases in health insurance costs for employees next year, given a challenging job market because of the pandemic.

The average employee contribution to an F.S.A. was just under $1,200 in 2019, according to the Employee Benefit Research Institute, which also found that nearly half of participants have forfeited all or part of their contributions. The median amount lost was $157. But because paycheck deductions are made pretax, employees shouldn’t fret too much about leaving behind relatively small balances, said Paul Fronstin, director of health research at the institute.

“It’s OK to lose a bit of money,” he said, “if you’re getting a tax break.”

To see how much you can save in taxes with an F.S.A., you can try using online calculators, like the one at FSAstore.com, which sells F.S.A.-eligible products.

There’s a caveat with all of the temporary changes, however. Any expansion of carry-over amounts or deadlines is at an employer’s discretion — and not all of them have made changes. About two-thirds of Willis Towers Watson’s clients made changes in carry-over rules for this year (for amounts retained from 2020), but fewer than half are doing so for next year, Ms. Myers said.

A survey of 2,200 shoppers in early September suggested that many workers were unsure if their employer had adopted any of the changes, said Rida Wong, president of Health-E Commerce, which operates FSAstore.com. About a quarter said they had higher balances in their accounts than at this time last year.

So pay close attention to benefits information sent by your employer, Ms. Wong said. And if you are still unsure whether rules for your F.S.A. have changed, contact your human resources office, she said.