Medicare Advantage Lets You In at 65 With No Questions. Medigap Asks Them Forever After. The Switch Most Retirees Can’t Make at 72

Medicare gives retirees two coverage options at age 65, the age the Centers for Medicare & Medicaid Services identifies as general Medicare eligibility. Medicare Advantage lets almost anyone enroll during almost any enrollment period, with no health questions asked.

Medigap works the opposite way. It offers one short guaranteed-issue window, and in most of the country insurers can then review every diagnosis, medication, and hospitalization before deciding whether to accept a retiree. By the time a 72-year-old wants to leave Medicare Advantage, the same rules that eased enrollment can block a later exit.

How Federal Law Limits Switching

Federal law forbids Medicare Advantage plans from using medical underwriting. A retiree with cancer, heart failure, or a long list of prescriptions can enroll during the Initial Enrollment Period, the Annual Election Period each fall, or an applicable Special Enrollment Period, and the plan cannot refuse them or charge more because they are sick. Medigap sits under a different rulebook. One federally protected window, the Medigap Open Enrollment Period, runs for six months and begins the first month a person is both age 65 or older and enrolled in Medicare Part B, according to the Centers for Medicare & Medicaid Services. During that window, any Medigap insurer selling in the state must offer any plan at its best available rate, regardless of health history.

After those six months close, federal protections end and state law governs. In most states, a Medigap insurer reviewing a later application can ask full health questions, charge a higher rate based on the answers, impose a waiting period of up to six months for a pre-existing condition, or decline the application entirely.

Why 72 Is the Wrong Age to Try

The retiree who picked a zero-premium Medicare Advantage plan at 65 often wants Medigap by 72, when prior authorization, narrow provider networks, and out-of-network billing start to matter, according to the Centers for Medicare & Medicaid Services. Healthcare spending for households headed by someone 65 or older has climbed with inflation: average annual expenditures reached $78,535 in 2024, up from $77,280 in 2023 and $72,973 in 2022, according to Centers for Medicare & Medicaid Services.

Meanwhile, the 2027 Social Security cost-of-living adjustment is tracking near 3.3%, and the Consumer Price Index at 334.1 in August 2026 is the highest reading in the available series. A retiree facing new medical bills on a fixed income may prefer Medigap’s more predictable cost sharing (the surcharges and coverage gaps that catch retirees off guard are the whole subject of our free Medicare guide). That interest typically comes up when underwriting requirements are hardest to meet.

States and Situations That Rewrite the Rules

A minority of states override the federal default. Connecticut, Massachusetts, and New York require Medigap insurers to issue policies on a continuous, year-round guaranteed-issue basis, so a resident can switch without underwriting at any time. Maine requires guaranteed issue for Medigap Plan A each year during a designated month. A larger group, including California, Oregon, Idaho, Illinois, Louisiana, Nevada, Oklahoma, and Washington, uses some form of annual switching right, often tied to the enrollee’s birthday, that lets a current Medigap policyholder move to an equal or lesser plan without underwriting.

Federal law also carves out situations that restore guaranteed issue. A retiree who enrolled in Medicare Advantage when first eligible at 65 has a 12-month trial right to drop the plan and buy any Medigap policy sold in the state without underwriting, according to Centers for Medicare & Medicaid Services. The same 12-month right applies to someone who dropped a Medigap policy to try Medicare Advantage for the first time. Guaranteed issue also triggers when a Medicare Advantage plan leaves the market, ends its contract in a service area, or the enrollee moves out of the plan’s coverage area.

What to Decide Before Part B Starts

A retiree approaching Part B enrollment is deciding whether to use the one federally protected chance to buy Medigap on the insurer’s best terms. Choosing Medicare Advantage at 65 in a state without continuous or annual guaranteed issue means accepting that a later switch may require passing medical underwriting as a 72-year-old, according to the Centers for Medicare & Medicaid Services.

A retiree already in Medicare Advantage and past the six-month Medigap window should confirm whether their state grants continuous, annual, or birthday-rule guaranteed issue, and whether any federal guaranteed-issue right currently applies to their situation. Missing the Medigap Open Enrollment Period does not always mean the plan is unreachable, but in most states, on most days, it means an insurer gets to decide whether to sell.

Contact [email protected] for any questions or corrections.