HSA funds are owned by the account holders, so they roll over from one year to the next and never expire. This makes them markedly different from flexible spending accounts (FSAs), which are often offered through employers. Generally speaking, a flexible spending account is a savings account that lets employees contribute a portion of their earnings to pay for medical expenses and dental bills. FSA contributions are also tax-advantaged, meaning they are deducted from the user’s taxable income. If an employee doesn’t use the money in their FSA by the end of the plan year, their account balance will disappear unless their employer offers a grace period of up to two-and-a-half months.