Beginning in 2013, the amount an employee can put into a cafeteria plan for health care costs is $2500.
Initially, these contributions were "use-it-or-lose-it" so an employee had to be very cautious about the amount they contributed so as to not leave anything at the end of the year. In 2005 the "use-it-or-lose-it" rule was modified to provide a grace period. Employers could permit employees to use amounts remaining from the previous year to pay for expenses made through March 15th of the following year.
The IRS has modified the "use-it-or-lose-it" rule once again. Employers have the option of allowing employees to carryover up to $500 of the amount they have set aside for health care expenses from one year to the next and use that to pay for qualified expenses throughout the entire year rather than just expenses made through March 15th. The carryover amount does not count against the $2500 contribution an employee can make each year.
Check with your employer to see if they are going to adopt the new carryover provisions.