The Medicare basics your parent will not admit they do not understand

Your dad has a stack of mail on the kitchen counter that includes at least three envelopes with the word MEDICARE in red, and when you ask him what he's signed up for he says, with great confidence, "the good one." He does not know which one is the good one. Neither, at this point, do you.

This is the moment to sit down at that same kitchen table and figure it out together, because Medicare has real deadlines and real financial penalties, and "we'll deal with it later" is how families end up paying an extra 10% on a monthly premium for the rest of a parent's life. Literally forever. That is not a scare tactic; that is how the late-enrollment penalty on Part B works.

Here is what the alphabet actually means, followed by the two decisions that matter more than any of the rest of it.

The alphabet, in the order it actually matters

Part A is the hospital part. If your parent or their spouse paid Medicare taxes for about ten years of work, Part A is free. It covers inpatient hospital stays, some skilled nursing after a hospital stay, hospice, and a sliver of home health. Almost everyone signs up for this at 65 and it is rarely the thing that causes drama. The drama is that Part A does not cover the doctor who visits them in the hospital. That is Part B. Yes, really.

Part B is the doctor part. Office visits, outpatient care, lab work, preventive screenings, the anesthesiologist, durable medical equipment, the ambulance. In 2024 the standard premium is $174.70 a month, and it goes up for higher-income retirees under something called IRMAA — the Income-Related Monthly Adjustment Amount, which sounds like a Swedish pop star and behaves like a tax. Part B is where the late-enrollment penalty lives: miss your window without other qualifying coverage and you pay 10% more per month for every 12 months you delayed. For life.

Parts A and B together are what people mean when they say "Original Medicare." It is a solid foundation with two significant holes: it does not cap your out-of-pocket costs, and it does not cover prescription drugs. Those holes are what Parts C and D are trying to solve, in two very different ways.

Part C is Medicare Advantage. A private insurance company — Humana, UnitedHealthcare, Aetna, a regional Blue Cross plan — takes over your parent's Medicare and bundles A, B, usually D, and often extras like dental, vision, and a gym membership. Premiums can be low or zero. In exchange, your parent uses that plan's network, gets referrals, and lives inside that insurer's rules. It is HMO logic applied to a 78-year-old.

Part D is prescription drugs, sold as a standalone plan if your parent stays on Original Medicare. Every plan has its own formulary — the list of drugs it covers and what tier each one sits on — and the cheapest plan for your neighbor may be the most expensive plan for your mother, because it depends entirely on which specific pills she takes.

Medigap, sometimes called Medicare Supplement, is the other option people forget to mention. It is a separate private policy that plugs the holes in Original Medicare — the 20% coinsurance, the deductibles, the lack of an out-of-pocket cap. You cannot have Medigap and Medicare Advantage at the same time. You pick a lane.

The two decisions that actually matter

Everything above is vocabulary. Here are the two forks in the road where families make expensive mistakes.

Decision one: enroll in Part B on time, or prove you have creditable coverage. The Initial Enrollment Period is a seven-month window around your parent's 65th birthday — the three months before, the birthday month, and the three months after. If they are still working at a company with 20+ employees and covered by that employer's plan, they can delay Part B without penalty, but they must have the employer complete a form called CMS-L564 when they eventually enroll. Get that form now, while HR still remembers who your parent is. If they are retired, on COBRA, or on an ACA marketplace plan, none of that counts as creditable coverage for Medicare purposes. COBRA especially — people assume it protects them and it does not.

Decision two: Original Medicare plus Medigap plus Part D, or Medicare Advantage. This is the choice that will shape every doctor visit for the rest of their life, and switching later is harder than the sales brochures suggest. Medicare Advantage is cheaper month to month and comes with perks. Original Medicare plus a Medigap plan costs more up front and lets your parent see essentially any doctor in the country who takes Medicare, with predictable bills. If your mother has a specialist she loves at a major medical center two states away, Original Medicare plus Medigap is usually the answer. If she is healthy, local, and cost-sensitive, Advantage may work fine — until it doesn't. The catch: in most states, if you start on Advantage and try to move to Medigap later, insurers can medically underwrite you and refuse, or charge more. The door swings one way.

The phone call to make this week

Before anyone signs anything, get a real picture of what your parent is currently on. Call 1-800-MEDICARE (1-800-633-4227). It is open 24 hours. Have your parent next to you because they will need to give verbal permission for you to speak on their behalf, or you can complete form CMS-10106, the Authorization to Disclose Personal Health Information, in advance.

Here is what to say when someone picks up:

Hi, I'm calling with my mother, [Full Name], date of birth [MM/DD/YYYY], Medicare number [from her red-white-and-blue card]. She gives permission for me to speak on her behalf on this call. I'd like to confirm exactly what parts of Medicare she is currently enrolled in, whether she has a Part D or Medicare Advantage plan on file, and when her next enrollment window opens. Can you walk me through what you see?

Write down what they tell you. Ask them to repeat plan names and effective dates. Ask if there are any pending applications or gaps in coverage. That call alone will save you three weeks of guessing.

Open your calendar right now and block 45 minutes this week — with your parent, on speaker, coffee in hand — to make that call to 1-800-MEDICARE and find out what they actually have. Everything else follows from knowing where you're starting.