Medicare covers a great deal — but the gaps catch people off guard. Here's a clear-eyed look at what you get and what you need to plan for.

Important: Medicare rules, costs, and coverage details change annually. Figures cited here reflect general guidance and may not reflect the current year's specifics. Visit Medicare.gov for current enrollment periods, premiums, and coverage details — and consider consulting a licensed Medicare specialist for advice specific to your situation.

Medicare is one of the most talked-about and least-understood features of American retirement. Most people reaching 65 know they'll be eligible. Far fewer have a clear sense of what it actually covers, what it doesn't, and what the practical implications are for their health and finances in retirement.

The gaps in Medicare coverage are not small. Understanding them in advance — rather than discovering them at the point of need — is among the most valuable pieces of retirement planning available.

The basic structure

Medicare has four main parts. Part A covers hospital care: inpatient stays, skilled nursing facility care after a hospital stay, some home health care, and hospice care. Most people pay no premium for Part A if they or their spouse has paid Medicare taxes for at least ten years.

Part B covers outpatient care: doctor visits, preventive services, lab tests, medical equipment, and some home health services. Part B has a monthly premium (check Medicare.gov for the current year's figure) and a deductible and coinsurance.

Part C is Medicare Advantage — private insurance plans approved by Medicare that typically bundle Parts A and B (and often D) with additional benefits. Part D covers prescription drugs.

What surprises people

The biggest surprise for most people is what Medicare does not cover. Dental care is not covered under original Medicare — not routine care, not fillings, not dentures. Vision care is not covered — not eye exams for glasses, not glasses or contact lenses. Hearing aids are not

covered, and at prices of $2,000 to $6,000 per pair, this is a significant gap for the substantial proportion of older adults with hearing loss.

Long-term care is perhaps the most significant gap. Medicare covers skilled nursing facility care only in very specific circumstances — after a qualifying hospital stay, for a limited period, and only for skilled nursing needs (rehabilitation, wound care, IV medication). It does not cover ongoing custodial care: the kind of daily help with bathing, dressing, eating, and moving that people with chronic conditions or dementia often need. This care — whether provided at home or in a facility — is paid for out of pocket, or by Medicaid if the person's assets fall below qualifying levels.

Cost sharing

Even for what Medicare does cover, there are significant out-of-pocket costs. Part A has a deductible per benefit period. Part B has a 20% coinsurance for most covered services after the deductible, with no cap on total out-of-pocket spending under original Medicare. A serious illness or hospitalisation can result in very large bills even with Medicare coverage.

This is the primary reason that Medigap (Medicare Supplement Insurance) policies exist. These private policies cover some or all of the gaps left by original Medicare — the deductibles, coinsurance, and copayments. They don't cover dental, vision, or hearing, and they have their own premiums, but they provide protection against catastrophic out-of-pocket costs.

Enrollment timing matters

One of the most consequential and least-known aspects of Medicare is enrollment timing. There are specific windows for enrolling in various parts, and missing them can result in permanent premium penalties and gaps in coverage.

The Initial Enrollment Period runs from three months before to three months after the month you turn 65. Missing this window without a qualifying employer coverage exception results in a late enrollment penalty for Part B that applies permanently — 10% added to the premium for every 12-month period of delay.

The rules around employer coverage and Medicare coordination are specific and worth reviewing carefully — ideally with a benefits counsellor or licensed insurance agent who specializes in Medicare, rather than a general financial advisor. The Medicare.gov enrollment guide and the State Health Insurance Assistance Program (SHIP) offer free, unbiased guidance.

Planning around the gaps

The most practical planning approach is to think about the three major uncovered areas — dental, vision/hearing, and long-term care — separately, since they require different solutions.

Standalone dental and vision plans are available and relatively affordable. Many Medicare Advantage plans include some dental, vision, and hearing benefits that original Medicare doesn't offer, which is part of their appeal.

Long-term care insurance, if purchased before significant health changes (ideally in the fifties or early sixties), can fund the care that Medicare won't. For those who didn't purchase it earlier, hybrid life/long-term care policies offer another route. For those without either, having a clear understanding of what Medicaid would cover — and what it would require in terms of spending down assets — is important forward planning. The Medicare supplemental coverage comparison tool can help compare options.

Medicare is excellent coverage for what it covers. The key is knowing its limits well enough to plan around them.

Official resources