Two three-letter accounts, one letter apart, with completely different rules — and picking wrong can cost you real money in December. Answer honestly; the traps get flagged either way.
1 · Are you enrolled in (or choosing) a high-deductible health plan?
HSA eligibility legally requires an HSA-qualified HDHP. Your plan name usually says "HDHP" or "HSA" — HR can confirm in ten seconds.
2 · Do you have big, predictable expenses in the next 12 months?
Braces, glasses, a planned procedure, ongoing therapy — things you can put a number on today.
3 · Could you leave some of the money untouched to grow?
HSAs roll over forever and can be invested — they're the only account that's tax-free going in, growing, AND coming out (for medical).
4 · How steady is your cash flow month to month?
FSAs front you the full year's election on day one; HSAs only hold what's been deposited so far.