HSAs: the best retirement account you're not using

The Health Savings Account is the best account in the entire US tax code and most people either don't know it exists or use it wrong. If you have an HSA-eligible health plan, pay attention.

Why it's special

Every tax-advantaged account gives you a tax break in one place: Traditional IRA gives you pre-tax in, taxed out. Roth gives you post-tax in, tax-free out. HSA does all three — pre-tax in, tax-free growth, tax-free out for qualified medical expenses. Zero taxes, ever, as long as the money eventually covers healthcare.

The secret: don't use it for current medical bills

Most people use their HSA as a debit card for doctor visits, which is fine but wastes the real power. The sophisticated play: pay medical expenses out of pocket, save the receipts, and let your HSA grow invested for decades. There is no time limit on reimbursing yourself. A $300 doctor visit you paid for in 2025 can be reimbursed from a much larger HSA balance in 2050, tax-free.

The retirement escape hatch

After age 65, you can use HSA money for any purpose. Non-medical withdrawals are taxed like a Traditional IRA (ordinary income, no penalty). So worst case, your HSA becomes a Traditional IRA at 65. Best case — if you accumulated medical receipts over the years — it stays tax-free forever.

Requirements

• You must be enrolled in an HSA-eligible High Deductible Health Plan (HDHP).
• You can't be enrolled in other non-HDHP health insurance or Medicare.
• You can't be claimed as a dependent on someone else's tax return.

The triple advantage, quantified

The payroll detail in that table deserves a spotlight: HSA contributions made through your employer's payroll skip Social Security and Medicare taxes too — a 7.65% bonus that even 401(k) contributions don't get. For someone in the 22% bracket with 5% state tax, each $1,000 contributed via payroll costs only about $653 of take-home pay. No other account gets close.

The mistakes that waste an HSA

• Leaving the balance in cash. Most HSA providers default to a 0.1% savings account; you usually have to click 'invest' manually once your balance passes a small threshold.
• Spending it down every year like an FSA. The HSA never expires and follows you between jobs — it's a portable investment account, not a spending card.
• Ignoring the employer contribution. Many HDHPs come with $500-1,500 of free employer HSA money that people forfeit by not opening the account.
• Losing receipts. The reimburse-yourself-later strategy is only as good as your documentation — a shared cloud folder with photographed receipts is the whole system.
• Contributing while on Medicare. Enrollment in any part of Medicare ends HSA eligibility, and Medicare enrollment can be retroactive up to six months — stop contributing early in the year you plan to enroll.

What counts as a qualified expense (more than you think)

The list of tax-free HSA uses is generous and getting more so: doctor visits, prescriptions, dental work, orthodontia, vision care including glasses and LASIK, mental health therapy, physical therapy, chiropractic care, fertility treatment, and — since 2020 — over-the-counter medications and menstrual products without a prescription. After 65, Medicare Part B, Part D, and Medicare Advantage premiums are qualified expenses too (though Medigap premiums are not), as are a portion of long-term care insurance premiums at any age based on your age bracket. The practical upshot: nearly everyone's retirement contains six figures of qualified expenses waiting to absorb HSA money tax-free, so the fear of 'over-saving' in an HSA is mostly imaginary.

Is an HDHP even right for you?

The honest caveat: don't pick a high-deductible health plan solely to unlock the HSA. If your family has high, predictable medical costs — ongoing prescriptions, therapy, a planned birth — a traditional plan with higher premiums but lower out-of-pocket exposure can beat the HDHP-plus-HSA combination even after the tax breaks. Run the total-cost math both ways during open enrollment: premiums plus expected out-of-pocket costs, minus employer HSA contributions and tax savings. For healthy households and those with employer HSA contributions, the HDHP usually wins; for heavy healthcare users, it's genuinely close.

The bottom line

If you're HDHP-eligible, the optimal play is mechanical: contribute the max through payroll, invest the balance in an index fund, pay medical bills out of pocket while photographing receipts, and let the account compound untouched for decades. Worst case it behaves like an extra Traditional IRA at 65; best case it's the only six-figure sum you'll ever spend that no tax authority ever touched.