What Is Medicare and How Does It Work?

Medicare is the federal health insurance program that covers most Americans starting at age 65. It also covers certain younger people with qualifying disabilities or specific medical conditions. If you are approaching 65 or helping a family member get ready for Medicare, understanding how the program is structured will make every decision after that easier.

This guide breaks down what Medicare actually is, how its parts work, and what choices you will face when it is time to enroll.

The Four Parts of Medicare

Medicare is not one single plan. It is a system made up of four distinct parts, each covering different types of care.

Part A: Hospital Insurance

Part A covers inpatient hospital stays, skilled nursing facility care (following a qualifying hospital stay), hospice care, and some home health care. Most people do not pay a premium for Part A if they or their spouse paid Medicare taxes for at least 10 years while working.

What Part A does not do is cover everything that happens inside a hospital. You may still face deductibles and coinsurance, especially for longer stays.

Part B: Medical Insurance

Part B covers doctor visits, outpatient care, preventive services, durable medical equipment, and many types of outpatient procedures. Unlike Part A, Part B requires a monthly premium — and that premium can vary depending on your income.

Part B is essential for most day-to-day medical needs, but it does not cover prescription drugs, dental care, vision exams, or hearing aids on its own.

Part C: Medicare Advantage

Medicare Advantage plans are offered by private insurance companies approved by Medicare. These plans bundle Part A and Part B benefits into one plan and often include additional coverage like prescription drugs, dental, vision, and hearing. They may also offer extras such as gym memberships or wellness programs.

Medicare Advantage plans typically use provider networks, meaning your access to doctors and hospitals may depend on the specific plan you choose.

Part D: Prescription Drug Coverage

Part D covers outpatient prescription medications. These plans are also offered by private insurance companies, and each plan has its own formulary — a list of drugs it covers. The cost of Part D depends on the specific plan, the drugs you take, and the pharmacy you use.

If you are using Original Medicare (Parts A and B) without a Medicare Advantage plan that includes drug coverage, a standalone Part D plan is usually the way to get prescription benefits.

How the Parts Fit Together

One of the most common sources of confusion is understanding how these parts combine. Here is the simplest way to think about it:

Path 1: Original Medicare + Supplement + Part D You enroll in Parts A and B (Original Medicare), add a Medigap policy to help cover out-of-pocket costs, and add a Part D plan for prescription drugs. This path gives you the most provider flexibility, since Original Medicare is accepted by most doctors and hospitals nationwide.

Path 2: Medicare Advantage (Part C) You enroll in a Medicare Advantage plan, which replaces your Original Medicare coverage. Most Advantage plans include drug coverage built in, and many add dental, vision, and hearing benefits. This path often has lower monthly premiums but may restrict your provider network.

Neither path is universally better. The right choice depends on your doctors, your medications, your budget, and how much flexibility you need.

• Medicare has four parts — A (hospital), B (medical), C (Advantage), and D (drugs) — and they serve different purposes.
• You have two main coverage paths — Original Medicare with supplements, or Medicare Advantage — and the best fit depends on your personal situation.
• Enrollment timing matters — missing key windows can result in penalties or gaps in coverage.

Who Is Eligible for Medicare?

Most people become eligible for Medicare at age 65. You may also qualify if you are under 65 and have received Social Security disability benefits for at least 24 months, or if you have End-Stage Renal Disease (ESRD) or ALS.

If you are already receiving Social Security benefits when you turn 65, you will typically be enrolled in Parts A and B automatically. If you are not receiving Social Security yet, you will need to sign up yourself during your Initial Enrollment Period — a seven-month window around your 65th birthday.

What Medicare Does Not Cover

Even with Parts A and B, there are gaps. Medicare generally does not cover:

• Routine dental care
• Routine vision exams or eyeglasses
• Hearing aids
• Long-term custodial care
• Most care outside the United States

This is one reason many people add supplemental coverage — either through a Medicare Advantage plan with extra benefits or through standalone dental, vision, or supplemental policies.

Where to Go From Here

Once the four parts make sense, the next question is usually what each one actually pays for — Medicare Part A vs Part B breaks that down covered service by covered service. Our how Medicare works overview walks through the mechanics, and when you are ready to weigh the two coverage paths, start with Medicare Advantage vs Medigap. Unfamiliar terms along the way are defined in our insurance glossary.

Summit Benefits Group helps individuals and families across Kentucky understand Medicare from the ground up. Whether you are approaching 65 for the first time, reviewing an existing plan, or helping a parent figure out their options, our team provides clear, no-pressure guidance tailored to your situation.

We do not push one path over another. We help you understand the tradeoffs, review your doctors and medications, and compare the options that actually apply to you.