Well, here is another place where I need this forum to open my mind. I didn't really see it as a major tax shelter and didn't think about the Medicare aspect. (The latter didn't enter my mind because when I first had an HSA account, I was 55.) Still, the interest isn't very much, so why not wait to see what I actually needed and then max out at the end of the year. Or even the first quarter of the next?
I'll tell you what has made it worthwhile for me, and you can see what applies to you.
I found an expense free HSA account at my credit union. It used to give 2%, now it's 1.5%. Not great, but not bad for the non-equity part of my asset allocation.
At some point when the balance gets high enough, I (may) move it to another account where I can invest in equity accounts for a fee. The balance needs to be high enough for the fee to be worthwhile. I should probably do it now, but haven't gotten around to it.
How do I get the balance up? I pay for medical expenses out of pocket, and let my HSA grow tax free. I keep the receipts so I can withdraw up to the amount of my expenses tax free at any time. This is a good emergency fund, or a way to bridge until I get more income from my SS and pension. I've only used it a little bit once. Otherwise I plan on holding it a lot longer, unless another need arises
Taking the HSA deduction gives me more room to do Roth conversions or take capital gains and still qualify for ACA deductions. This is probably the biggest benefit for me, so I definitely want to make the max contribution.
There are threads you can search for to find the best place to open an HSA tax free, or low fee with good investment options.
It's not game changing money but it's an easy benefit to take, and I'm close to $40K in my HSA now, still growing tax free.