Medigap vs. Medicare Advantage: Which Is Right for You?

Two Philosophies of Coverage, One Fork in the Road

At age 65, Medicare enrollees face a binary choice that most financial advisors consider the single most consequential health insurance decision of retirement. Medigap (Medicare Supplement) fills the gaps in original Medicare — the 20% coinsurance, hospital deductibles, and unlimited out-of-pocket exposure. Medicare Advantage replaces original Medicare entirely, bundling hospital, outpatient, and often drug coverage into one private plan, usually with a $0 or low monthly premium and a defined out-of-pocket maximum. The right answer depends entirely on your health, geography, and financial situation.

Head-to-Head Comparison

Medigap Plan G: The Current Gold Standard

Plan F was the most comprehensive Medigap policy until Medicare Access and CHIP Reauthorization Act (MACRA) banned it for beneficiaries newly eligible after January 1, 2020. Today, Plan G is the most comprehensive available to new enrollees. It covers the Part A hospital deductible ($1,632 in 2024), Part B coinsurance (the full 20%), skilled nursing coinsurance, foreign travel emergencies (80% up to $50,000 lifetime), and excess charges when doctors bill above Medicare's approved amount.

Plan G leaves only one gap: the Part B annual deductible of $240 (2024). After paying that $240 out of pocket, virtually all covered Medicare services cost nothing for the remainder of the year. The predictability is absolute. A $500,000 cancer treatment costs the Plan G enrollee $240. Zero surprise bills.

• Plan N is a lower-premium alternative covering everything Plan G does except Part B excess charges; also requires $20 copays per physician visit and $50 for emergency room visits
• High-deductible Plan G (HD-G) has a $2,800 deductible (2024) before Medigap benefits kick in; premiums can be 40–60% lower
• Premiums for the same plan vary by insurer using attained-age, issue-age, or community-rated pricing models — the pricing model matters over a 20-year retirement

Medicare Advantage: The Trade-Off in Practice

Medicare Advantage plans attracted 33.5 million beneficiaries in 2024. The appeal is obvious: extra benefits at lower cost. A typical Plan HMO in a major metro area might cost $0/month above Part B, include dental cleanings, vision hardware allowances, hearing aids, gym memberships, and over-the-counter drug allowances. For a healthy 65-year-old with local providers in-network, the value proposition is compelling.

The limitation emerges with serious illness. The $8,850 in-network out-of-pocket maximum (2024 CMS-mandated cap) sounds protective — and it is, compared to original Medicare without Medigap. But it is not zero. Cancer, cardiac surgery, or major orthopedic work can drive costs to the cap. Out-of-network costs have separate, higher caps, and some services require prior authorization that original Medicare would process automatically.

Real Scenario Comparison

The Switching Problem

The asymmetry in switching rights is the most critical — and least understood — aspect of this decision. Enrolling in Medigap during the initial open enrollment period (the six months after Part B begins) guarantees acceptance regardless of health conditions. After that window closes, Medigap insurers can medically underwrite applicants in 47 states. They can charge more or deny coverage based on health history. Cancer survivors, heart disease patients, and diabetics may find Medigap unavailable or prohibitively expensive if they try to switch from Medicare Advantage after developing health issues.

Three states — Connecticut, Maine, and New York — require guaranteed-issue Medigap enrollment year-round, regardless of health. Massachusetts uses its own standardized plan names. In all other states, the decision made at 65 may be irreversible without a guaranteed-issue event (moving out of a plan's service area, insurer leaving the market, etc.).

• Switching from Medigap to Medicare Advantage is allowed annually during AEP (Oct 15 – Dec 7) and is easy; going back may be medically underwritten
• Medicare Advantage beneficiaries get one opportunity to switch to original Medicare and enroll in Medigap with guaranteed issue: the Medicare Advantage Disenrollment Period (Jan 1 – Mar 31) within the first year of enrollment only
• Five-star Medicare Advantage plans allow enrollment any time during the year via a Special Enrollment Period

Geographic and Income Considerations

Rural enrollees face the sharpest Medigap premium spikes — a 70-year-old in rural Kentucky may pay $400+/month for Plan G. For high earners already paying IRMAA surcharges on Part B, adding a $300+ Medigap premium creates significant fixed monthly health costs. Meanwhile, urban areas with dense Medicare Advantage networks and $0 premium plans may deliver equivalent access with fewer costs for the statistically healthy.

The calculus changes with age. A 65-year-old purchasing Medigap begins with lower absolute risk but pays premiums for potentially 30 years. A 65-year-old in Medicare Advantage gambles that serious illness won't hit before switching becomes medically impossible. The mathematically optimal choice depends on actuarial tables, risk tolerance, and geography — not on which plan looks better in a brochure.

This article is for informational purposes only and does not constitute financial advice.