Sources and how the rules are checked

How they’re checked

• Each rule was checked against the text of the official page it cites. No AI writes or checks the rules.
• Every week, the rules and links are re-checked against those pages, and any change is reviewed before it goes live.
• Each fall, CMS publishes the next year’s premiums and income limits. The figures here are for 2026: a standard Part B premium of $202.90 a month.
• A review by a SHIP Medicare counselor is planned. Until then, treat this as a starting point and confirm your dates with SHIP or Social Security.

What each part of your plan is based on

Your first sign-up window

7 months: the 3 months before the month you turn 65, that month, and the 3 after. Born on the 1st, Medicare counts you as turning 65 a month earlier. Medicare.gov: When can I sign up? · Medicare.gov: When does Medicare coverage start?

When coverage starts

Sign up before the month you turn 65 and it starts on the 1st of that month; sign up later and it starts the month after. Medicare.gov: When does Medicare coverage start?

Waiting on Part B while working

Only coverage from a current job (yours or your spouse's) at an employer with 20 or more employees. Then you get 8 months after work stops. COBRA and retiree plans don't count. Medicare.gov: Working past 65 · Medicare.gov: When can I sign up?

Late penalties

Part B: 10% more for each full 12 months you could have had it, for life. Part D: added if you go 63 days or more without creditable drug coverage. Medicare.gov: Avoid late enrollment penalties

Drug plans

Join in your first window, or within 2 full months after the month job coverage ends. Medicare.gov: Special Enrollment Periods · Medicare.gov: Your coverage options

Medigap

A one-time 6-month window from the first month you have Part B and are 65 or older, when insurers can't turn you down for your health. Medicare.gov: When can I buy Medigap?

HSA contributions

None for any month you have Medicare. Part A can be backdated up to 6 months when you sign up after 65. IRS Publication 969 (HSAs) · Medicare.gov: Working past 65

Marketplace plans

They don't end on their own when Medicare starts. You can report your Medicare start date up to 3 months ahead. HealthCare.gov: Medicare and the Marketplace

Income surcharge (IRMAA)

Premiums use your tax return from 2 years earlier. In 2026 it starts above $109,000 (single) or $218,000 (joint). Form SSA-44 can lower it after you stop working. Medicare.gov: Medicare costs · CMS: 2026 premiums and deductibles · Form SSA-44 (lower your IRMAA)

Missed a window

The General Enrollment Period runs January 1 – March 31, with coverage from the month after you sign up. Medicare.gov: When does Medicare coverage start? · Medicare.gov: Avoid late enrollment penalties

What this guide leaves out

• Medicare through disability, ESRD or ALS (before 65). Different rules apply.
• Medicaid and Extra Help. Your SHIP counselor can check whether you qualify.
• State Medigap rules beyond Connecticut and New York, which sell Medigap all year without health questions. About 15 states add their own rights, and they change often.
• Part A premiums for people without 10 years of Medicare-taxed work. Most people get Part A free.
• Exact penalty amounts in dollars. The plan states the rule instead.

All sources