Whether it's safe to delay Medicare while working past 65 turns on a small set of published rules: who pays primary (which hinges on employer size), the HSA six-month lookback, and the 8-month Special Enrollment Period after employment coverage ends. We apply those rules to your answers and return a verdict with the reasons.

Step by step

1. Employer of 20 or more: the employer plan pays primary, so delaying Part B while covered is generally penalty-free — you get an 8-month Special Enrollment Period when employment coverage ends.
2. Employer of fewer than 20: Medicare pays PRIMARY at 65 even if you stay on the employer plan — without it the plan may pay almost nothing, so the verdict is to enroll now.
3. HSA contributions: enrolling in Medicare (even just Part A) ends HSA eligibility, and Part A can start retroactively — so contributions should stop about six months before it begins.
4. Retiring within a few months: delay buys little and the enrollment clock is about to start, so the verdict flags the delay as risky and points at the timeline instead.

Sources & assumptions

• Medicare.gov — "Working past 65" and "How Medicare works with other insurance" (coordination-of-benefits rules).
• CMS "Medicare & Other Health Benefits: Your Guide to Who Pays First".
• IRS Publication 969 (HSAs and Medicare enrollment).

Note: Nothing proprietary — the verdict applies the public rules above; every reason is shown with the result.

1. This is an educational rule-of-thumb check, not enrollment advice or an eligibility determination — confirm your situation with Medicare, Social Security, and your benefits administrator.
2. COBRA and retiree coverage do NOT count as employer coverage for delaying Part B — the 8-month Special Enrollment Period runs from when your EMPLOYMENT coverage ends, even if COBRA continues.
3. If you contribute to an HSA, contributions must stop about six months before Medicare Part A begins — Part A starts retroactively, and overlapping contributions can trigger tax penalties.
4. This tool is not affiliated with or endorsed by Medicare, CMS, or any government agency.