Flexible spending accounts (FSAs) allow taxpayers to set aside pre-tax dollars to pay for out-of-pocket medical expenses.

The drawback has been the fact that unused amounts each year are forfeited. Plans could provide a 2½ month grace period to use up unspent set-asides.

Now a change announced by the IRS adds more flexibility to these accounts. Plans can be modified by employers to allow up to $500 of unused amounts to be carried over into the following year. Health FSAs cannot have both the old 2½ month grace period and the $500 carryover; they can have one or the other (or neither).