Medicare
Medicare tests eligibility, enrollment timing, cost-sharing, and the interaction between Original Medicare, Medicare Advantage, Part D, and Medigap. Most missed questions involve penalties and enrollment windows.
Eligibility and parts
- Part A (hospital) - 65+ with 40 quarters of Medicare-covered work (or a spouse's record), or disability benefits for 24 months, or ALS/ESRD. Premium-free with 40 quarters; otherwise a premium applies. Covers inpatient hospital, skilled nursing after a qualifying 3-day inpatient stay, hospice, and some home health.
- Part B (medical) - physician services, outpatient care, durable medical equipment, preventive care; voluntary and premium-based (2024: $174.70 standard premium, $240 deductible).
- Part C (Medicare Advantage) - private plans delivering A and B, often with drug coverage; networks and prior authorization apply.
- Part D - prescription drug coverage, stand-alone or bundled into MA.
Enrollment
Initial Enrollment Period is seven months - three before the birthday month, the birthday month, three after. Annual Open Enrollment runs October 15–December 7 for January 1 changes; the Medicare Advantage Open Enrollment Period runs January 1–March 31 for one change. Delayed Part B enrollment is permitted while working for an employer with 20 or more employees.
Penalties and Medigap
- Part B late penalty: 10% of the standard premium for each full 12-month delay, for life.
- Part D late penalty: 1% of the national base beneficiary premium per uninsured month, rounded to the nearest $0.10.
- Medigap: standardized plans A–N; Plans C and F are closed to those newly eligible after January 1, 2020. A six-month guaranteed-issue window starts when you are 65 and enrolled in Part B. Medigap cannot be paired with Medicare Advantage.
Worked example
A beneficiary delays Part B for 26 months. Twenty-six months contains two full 12-month periods, so the penalty is 20% of $174.70 - about $34.94 - added to the premium for life, roughly $209.64 per month.
Traps
Thinking observation status satisfies the 3-day SNF requirement; assuming Medigap and Medicare Advantage can coexist; believing the Part D penalty is a flat fee; forgetting that employer coverage only permits delayed Part B if the employer has 20 or more employees; and overlooking IRMAA income surcharges.