My experience with health savings accounts over 6 years — the good, the bad, and what I'd tell my past self.

The good: the triple tax advantage is genuinely unmatched for someone in a moderate-to-high tax bracket. I've been investing my HSA contributions rather than spending them, and the balance has grown to $31,000 over 6 years. I pay current medical expenses out of pocket and keep all receipts — there's no statute of limitations on reimbursing yourself for qualified medical expenses, so that $31,000 is available for any reason if I ever have a large documented medical expense from any prior year.

The less obvious part: not every HSA provider allows investing. Some keep your entire balance in cash. If your employer's default HSA custodian doesn't offer investment options or charges fees for them, you can transfer to a better provider like Fidelity annually.

What I'd tell my past self: open an HSA, invest the entire balance in VTI, pay all current expenses out of pocket, and keep every medical receipt in a folder. You're building a tax-free medical expense fund that can also serve as a Roth IRA equivalent after 65.