I'm starting a brand new HDHP and HSA this year, and I want to make sure I understand how it works...
My deductible and out-of-pocket are $13,100 (family) with insurance, and I also plan on spending money that is not covered by insurance at all.
The 2018 limit for HSA contribution is $6,900.
Assuming I fully fund the $6,900 to the HSA account, but spend more than $6,900 in medical expenses this year, what do I do? I've read that say I can pay with my own money then reimburse myself later, but does that apply over multiple years?
For example, suppose I spend $8,000 in 2018. Would I:
Spend $1,100 of my personal money and claim that as a deduction on my 2018 income tax (if it's above the 10% threshold)?
Spend $1,100 of my personal money, ignore it for income tax purposes in 2018, then sometime in 2019 transfer $1,100 from HSA back to my personal account?
EDIT As a followup to that, suppose in 2019 I don't have an HSA (like if I get a job with super-awesome low deductible insurance and have to give up the HSA account). What happens to that $1,100? Do I just lose any potential tax benefit for it?