HSA funds will automatically roll over and accumulate year to year if not spent. Unlike HSA plans, your FSA funds will not always carry over. Before the Affordable Care Act, a significant disadvantage of using an FSA account was that funds left over at the end of the year would not carry over to the following year. Now, some plans permit up to $500 to be carried over. If you are unsure if your plan allows for rollovers, contact your insurance provider for clarification.