I'm really on the fence on HSAs. I think certain ones have their place (employer match, etc) but many are a fixed amount, don't roll over, and the tax savings are really close to zero. My fiance's HSA is like that, $2000/year, half of which is provided by her employer which is kinda nice but it expires at the end of every year.
I kinda feel like a better option is simply a savings account... some of those HSAs market themselves as the best thing ever but in reality they just charge you to park your money somewhere and keep it if you don't use it. Not a good deal.
Don't confuse a HSA with a FSA.
The Flexible Spending Account (FSA) is where you (pre tax) and your employer can contribute money to it annually, but you must use all funds by the end of the calendar year (used to be March 31st of the following year I believe). The only positive thing I have seen in you get the money you allocate to the FSA up front when it is done through an employer (If you say you will contribute $1,000 for the year, you get that $1,000 in January and make payments towards it all year). FSA is usually comes with a co-pay type health insurance plan.
The Health Spending Account (HSA) is one you (pre tax) and your employer can contribute to and it never expires. Will always roll over. There are individual HSA's out there too. HSA usually comes with a high deductible health plan option. You have to build up funds in a HSA, no advance for the year on what you will contribute.
My employer offers good health insurance and offers a co-pay type plan and a high deductible plan. If you chose the high deductible plan, they will give you two deposits a year into the HSA.
I chose the HSA for me and my wife and put the difference that I saved from the co-pay type as a deposit into my HSA bi-weekly. Good thing about an HSA is you can carry it all the way to retirement, and then access it tax free. That is my plan, we ended up using more of it last year than I wanted, but I just upped my contribution this year. My goal is to get where I can contribute the max amount allowed by the IRS a year and keep rolling it over to retirement. You can also use it as an investment account once it reaches certain values.
That is part of my planning for retirement anyhow.....