Medicare and Other Health Insurance
The parts
Part A - hospital insurance: inpatient stays, skilled nursing after a qualifying stay, hospice, some home health. Premium-free with 40 quarters of work history. Part B - medical insurance: physician services, outpatient care, durable medical equipment, lab work; there is a monthly premium (income-related for higher earners) and 20% coinsurance with no out-of-pocket cap. Part C (Medicare Advantage) replaces Original Medicare with a private network plan, usually including drug coverage. Part D - outpatient prescription drug plans.
Enrollment
Initial Enrollment Period: seven months around the 65th birthday. Annual Enrollment: October 15–December 7 for changes effective January 1. Medicare Advantage Open Enrollment: January 1–March 31 (one change). General Enrollment: for those who missed Part B, with penalties. Part B late penalty is 10% per 12-month period of delay; Part D penalty is 1% of the national base premium per uncovered month.
Medigap and other coverage
Medigap (Plans A–N) supplements Original Medicare and cannot be used to pay Medicare Advantage cost sharing. Working past 65 with employer coverage may allow delayed Part B. Medicaid covers low-income individuals and can pay Medicare premiums for dual eligibles. Medicare does not cover custodial long-term care, routine dental, vision, or hearing.
Traps
- Medicare Advantage is an alternative to Original Medicare, not a supplement to it.
- Hospice is covered; custodial nursing home care is not.
- COBRA coverage generally does not delay Medicare enrollment obligations.
- Part D enrollment is voluntary but carries a permanent late penalty.
Rule of thumb
If a scenario asks how a 67-year-old with Original Medicare pays a hospital bill, the answer is Part A (after the deductible) plus Part B for physician charges - with Medigap or Medicaid filling gaps.