Re: Leftover HSA money vs. FSA reimbursements.
You can't get the $20 from two sources. Both HSA and FSA are a way of putting your own money aside to later use for medical expenses. If the bill is $20 and you get $40 you've been over reimbursed. Talk to a financial adivsor, I believe it's possible to keep an HSA indefinitely, sort of meant to be a long term savings account for costs now or in the future. If you have an HSA set up you may also be able to contribute to it so when in your retirement years, for example, you can use that money for health costs.
But the FSA you must use in the year in which you set the funds aside. Also be aware that FSA rules changed significantly this year, you can no longer use them for over the counter medications unless you can match the purchase to a prescription for OTC medications or treatment (i.e. band aids, etc). Thus my husband opted not to enroll in the FSA this year as we didn't want to chase down prescriptions for tylenol, etc.
Rt thumb fusion '13. R&L thumb arthroplasty '12 ; RT TKR & Bilat CTS' 11. Fusions: L5-S1('87), L4-S1('93), C5-C7('06), L3-S1('10), C4-C5('13). C5-C7 foraminotomy '08