Publication 502 and 503 provides assistance for filing Federal income tax returns and includes detailed information about eligible expenses and can be used as a reference for your FSA. Please note that while the Publication state expenses can be claimed as they are paid, this is only applicable for your Federal income taxes. For your FSA, you can claim expenses based upon when the services are provided, not when payment is made.
Also, even though insurance premiums and long-term care expenses are listed in Publication 502 as eligible health care expenses, they are not eligible for reimbursement through your FSA.
Publication 502 (Health Care Expenses)
Publication 503 (Dependent Care Expenses)