Coruscation

By using pretax dollars, you can reduce your overall cost for these items by about 20 percent, estimates Jennifer Calhoun, a principal with Mercer Health and Benefits, a consulting firm.

Another attraction had been the extremely generous list of eligible health expenses -- including deductibles and co-pays, eyeglasses and dental work, over-the-counter cold medicine, sunscreen and vitamins. But under the new law, starting Jan. 1, flex-spend users will no longer be able to submit claims for over- the-counter medicines unless they have been specifically directed to use them by a doctor.

For many consumers, having to start paying for cough drops or Tylenol with after-tax dollars probably is not a big deal. But the change will probably be felt by people with chronic illnesses who depend on drugs that have gone from prescription-only to over-the-counter status, like Claritin or other allergy medicines, or heartburn pills like Pepcid, Ms. Calhoun said.

And there is another big flex-spend change ahead: starting in 2013 the annual limit that any employee may contribute to these plans will be restricted to $2,500. Many companies had allowed much more.

The policy rationale for that change is simple. As the health law ushers in more comprehensive, affordable coverage, Kelly Traw, a principal at Mercer's Washington Resource Group, said the assumption was that employees would have less need for flexible spending accounts. And the revenue the government may get by limiting this tax break is meant to help finance the nation's health care overhaul.

If you look only at the averages, the new cap actually seems more than adequate. Although about 85 percent of companies with 500 or more workers offer health care flexible spending benefits, only 27 percent of eligible employees use them, according to Mercer. And the average account annual account balance is about $1,400 -- far less than even the new limit.