Many flexible spending health-care account holders have to use the money in their accounts soon, or they will lose it.

Financial advisors who have clients with money in flexible spending accounts should review the accounts with their clients within the next few days to make sure all of the funds are used, warned Rachel Rouleau, compliance director for the FSA Store, an online retailer that offers consumer education and offers FSA eligible products.

Many flexible spending account holders have only until March 15 to use the money in the account. FSAs are sponsored by employers and allow employees to contribute money, before taxes are deducted, to the account. The money has to be used for health-related expenses during the plan year, which usually means by Dec. 31. If money is not spent, it reverts to the employer to cover administrative costs.

But plans can have varying rules. Some plans allow as much as $500 to be rolled over to the next year and some have an extended deadline, which allows money to be taken from the accounts until March 15 of the following year.

“Approximately 35 million people have flexible spending accounts and 80% of them have money left in their accounts after Dec. 31,” said Rouleau. For those who have an extended deadline for spending the money—which means they have until  March 15 to use the funds—they should schedule necessary medical procedures or checkups now, she added.