Medicare Basics

Understanding Medicare: Parts A, B, C & D — Plus Penalties to Avoid

A plain-language guide to how Medicare is structured, the two late-enrollment penalties worth knowing about before you enroll, and what still-working 65-year-olds should check first.

What Medicare Parts A, B, C, and D Actually Cover

Medicare isn’t one program — it’s four parts that cover different things. Here’s the plain-language version:

• Part A (Hospital Insurance) — covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Most people pay no premium for Part A because they (or a spouse) paid Medicare taxes while working.
• Part B (Medical Insurance) — covers doctor visits, outpatient care, preventive services, and durable medical equipment. This one has a monthly premium, and it’s the part with a late-enrollment penalty if you sign up late without other creditable coverage (more below).
• Part C (Medicare Advantage) — an alternative way to get your Part A and Part B benefits, sold by private insurers approved by Medicare. Many Medicare Advantage plans bundle in Part D drug coverage and extra benefits like dental, vision, hearing, OTC allowances, and transportation — which is what our benefit pages walk through by topic and ZIP code.
• Part D (Prescription Drug Coverage) — covers prescription medications, either as a standalone plan alongside Original Medicare, or bundled into a Medicare Advantage plan. Like Part B, it has its own late-enrollment penalty.

Original Medicare is Parts A and B together. Medicare Advantage (Part C) is the alternative path, usually with Part D built in.

Late Enrollment Penalties: Part B and Part D

Medicare’s late-enrollment penalties are permanent — they get added to your premium for as long as you have that coverage, so it’s worth understanding them before your enrollment window passes.

• Part B penalty: your premium goes up 10% for every full 12-month period you were eligible for Part B but didn’t enroll and didn’t have other creditable coverage (like a current employer’s group plan). This penalty doesn’t go away — it’s added to your premium for as long as you have Part B.
• Part D penalty: calculated as roughly 1% of the national base beneficiary premium for every full month you went without Part D or other creditable drug coverage, added to your Part D premium for as long as you have Part D.

The good news: both penalties are avoidable. If you have creditable coverage — most commonly through a current employer — you can delay enrolling without a penalty. The key word is creditable, and it’s worth confirming your coverage actually qualifies before assuming you’re safe to wait.

Still Working Past 65? How It Affects Your Part B Premium

If you’re still working at 65 and covered by a current employer’s group health plan (generally one with 20 or more employees), you can usually delay Part B without a penalty — as long as that coverage counts as creditable.

A few things worth knowing:

• It has to be current, active employer coverage. Retiree coverage and COBRA do not count as creditable for this exception, even though they can feel similar day to day. This is the detail that catches people out most often.
• You get an 8-month Special Enrollment Period to sign up for Part B once your employment or that employer coverage ends — whichever comes first. Missing this window is what triggers the late-enrollment penalty described above.
• Delaying Part B does not delay Part A for most people, since most people pay no Part A premium. Most people keep Part A even while still on employer coverage.

If you’re approaching 65 and still working, a quick review of your employer plan can confirm whether you’re actually covered to delay — worth doing before your Initial Enrollment Period closes, not after.

Common Concerns We Hear — and How a Plan Review Addresses Each One

• “Will I lose my doctor?” Medicare Advantage plans use provider networks, so out-of-network care can cost more or not be covered. A review checks whether your specific doctors and hospital are in-network before you enroll, not after.
• “Is this actually $0, or is that misleading?” A low or $0 premium doesn’t tell the whole story — copays, deductibles, drug costs, and the out-of-pocket maximum all matter. We walk through what a plan actually costs you across a typical year of care, not just the premium.
• “Will my medications be covered?” We check your specific drug list against a plan’s formulary and tier placement, and confirm which pharmacy works best — before you’re stuck finding out at the counter.
• “Will I need approval for everything?” Referrals and prior authorization are more common under Medicare Advantage than Original Medicare, and they’re a real source of frustration. We’re upfront about which plans use more of this and which use less.
• “What do dental/vision/hearing/OTC actually get me?” Extra benefits sound great in a brochure, but limits and access rules vary a lot by plan. We explain the actual limits — annual maximums, how often, which providers — not just that the benefit exists.
• “I don’t fully understand my options, and I don’t love getting sales calls.” That’s normal — Original Medicare, Medicare Advantage, Part D, and Medigap genuinely overlap in confusing ways. A review costs you nothing, there’s no obligation, and we don’t need your Medicare number just to compare plans with you.

Want help applying this to your own situation? Request a plan review or call a licensed insurance agent at (832) 734-6825 (TTY 711) — I will walk through your specific doctors, prescriptions, and budget with you.