Making Sense of Medicare: A Guide for Women Approaching 65
If you're approaching 65, Medicare is probably on your radar. It’s one of those topics that can start to feel more complicated the closer you get to it. There are a few more decisions involved than most people expect:
Which parts do you need? What does each one cover? What's the difference between Medigap and Medicare Advantage — and how do you choose between them? What happens if you miss an enrollment window?
I wrote this post because I want women approaching 65 to have a clear picture of what the Medicare decision process actually involves before they're staring down an enrollment deadline. It's not the most exciting topic, but getting it right matters, and getting it wrong can be expensive.
Here’s what you need to know.
The four parts of Medicare — what each one actually covers
Medicare is divided into parts — A, B, C, and D — each covering different aspects of healthcare.
Part A — Hospital Insurance
Part A covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health services. Note that skilled nursing facility coverage is limited — the first 20 days are covered at 100%, days 21 through 100 require a daily co-pay, and coverage stops entirely after 100 days.
For most people Part A is premium-free. If you or your spouse worked and paid Medicare taxes for at least ten years, you've already paid for Part A through payroll taxes.
Part A does have deductibles and cost-sharing. The inpatient hospital deductible changes annually ($1,736 in 2026), but the premium-free nature of Part A makes it a straightforward decision for most people.
Part B — Medical Insurance
Part B covers outpatient care including doctor visits, preventive services, lab tests, durable medical equipment, and some home health services. Unlike Part A, Part B comes with a monthly premium. The standard premium adjusts annually ($202.90/month in 2026), and higher-income individuals pay more through IRMAA surcharges, which I'll cover below.
Part B also has an annual deductible and requires you to pay 20% of the Medicare-approved amount for most services after the deductible is met. That 20% coinsurance with no annual cap is one of the most important things to understand about original Medicare, and one of the primary reasons most people add supplemental coverage on top of Parts A and B.
Part D — Prescription Drug Coverage
Part D covers prescription medications through private insurance companies approved by Medicare. Each plan has a formulary (a list of covered drugs) and costs vary significantly between plans. It's worth comparing plans based on your specific medications and the pharmacies you use rather than simply choosing the lowest premium.
Part C — Medicare Advantage and the Medigap Alternative
Before getting into Part C, it's worth understanding the gap it's designed to fill, and the other way to fill it.
Original Medicare covers a significant portion of your healthcare costs but leaves gaps. The biggest one is the 20% Part B coinsurance with no annual cap. If you have a serious illness or an extended hospital stay, that 20% can add up quickly.
There are two ways to address that gap:
The first is Medigap (also called Medicare Supplement Insurance) which is private insurance that is paired with Medicare to fill in gap in what original Medicare doesn't cover. With a solid Medigap plan your out-of-pocket costs become largely predictable, and you can see any doctor who accepts Medicare without worrying about networks or referrals. The tradeoff is that Medigap premiums can be significant, often in the range of $150 to $300 or more per month depending on your age, location, and the plan you choose. You'll also need a separate Part D plan for prescription coverage since Medigap generally doesn't include it.
The second way to address the gap is Part C — Medicare Advantage. Rather than staying with original Medicare and adding Medigap on top, Medicare Advantage replaces original Medicare entirely with a private insurance plan. These plans must cover everything original Medicare covers and often include additional benefits like dental, vision, and hearing coverage that original Medicare doesn't provide. Premiums are often lower than Medigap (sometimes as low as $0 beyond your Part B premium) and many plans include drug coverage as well.
The tradeoffs with Medicare Advantage are meaningful. You'll generally need to use doctors and hospitals within the plan's network. Prior authorization requirements can add friction to getting care. And out-of-pocket costs can be significant if you have a serious illness or need extensive care.
The fundamental choice: original Medicare plus Medigap, or Medicare Advantage
This is the most important decision most people face when enrolling in Medicare. In simple terms: Medigap gives you predictability and flexibility at a higher monthly cost. Medicare Advantage gives you lower monthly premiums with more restrictions on how and where you get care.
Which option I recommend and why
In my experience working with women approaching retirement, the flexibility of original Medicare plus a solid Medigap plan is almost always worth the higher premium. The ability to see any Medicare-accepting doctor without prior authorization, without network restrictions, and without worrying about whether a specialist is covered is valuable. Healthcare decisions are stressful enough without adding insurance complexity on top of them.
For someone who is healthy, comfortable with a managed care environment, and focused on minimizing monthly costs, Medicare Advantage can be a reasonable choice. But I'd encourage anyone considering it to think carefully about what they're trading away — especially the Medigap enrollment window, which I'll explain next.
The Medigap enrollment window — why timing matters
This is one of the most important and least understood facts about Medicare.
When you first enroll in Part B, you have a six-month Medigap open enrollment period during which insurance companies cannot deny you coverage or charge you more based on your health history. After that window closes, Medigap insurers in most states can use medical underwriting, meaning they can deny your application or charge significantly higher premiums based on pre-existing conditions.
This window does not come back. If you start with Medicare Advantage and later want to switch to a Medigap plan, you may find yourself unable to get coverage (or priced out of it) because of health conditions that developed after your initial enrollment window closed.
For this reason, many people, particularly those in good health who want to preserve their options, choose to enroll in Medigap during the initial open enrollment window rather than starting with Medicare Advantage. The short-term premium savings of Medicare Advantage aren't always worth giving up that protection.
The late enrollment penalty
If you don't enroll in Part B when you first become eligible, and don't have qualifying coverage from an active employer plan, you'll face a late enrollment penalty of 10% of the Part B premium for each full twelve-month period you were eligible but didn't enroll. This penalty is permanent.
The same principle applies to Part D — a late enrollment penalty accumulates for each month of delay without drug coverage, also added permanently to your premium.
The rules around employer coverage and enrollment windows are nuanced, particularly for people still working at 65 or covered under a spouse's employer plan. Make sure you understand your specific situation before assuming you can delay enrollment without consequences.
IRMAA — the income-related premium surcharge
If your income exceeds certain thresholds, Medicare charges higher premiums for Parts B and D through a surcharge called IRMAA. The thresholds adjust annually — in 2026 the surcharge begins at a modified adjusted gross income of $109,000 for a single filer and $218,000 for joint filers — but the concept is consistent: higher income means higher premiums.
IRMAA is based on your income from two years prior, which creates both a risk and a planning opportunity worth understanding.
The risk: large one-time income events within retirement — a home sale, a significant retirement account withdrawal, or a large Roth conversion — can spike your reported income for one year and trigger IRMAA surcharges two years later, even if your ongoing income is well below the threshold.
The planning opportunity: if you've recently retired and your income has dropped significantly from your working years, you may be able to file Form SSA-44 with Social Security to request that Medicare use your current lower income rather than the higher figure from two years ago. Retirement is one of the specifically listed qualifying events, and filing SSA-44 can eliminate or meaningfully reduce surcharges in the early years of retirement.
Both the risk and the opportunity are worth thinking through carefully in the years leading up to retirement. Large income decisions — when to sell assets, how much to convert to a Roth, how to sequence withdrawals — can have a direct and sometimes surprising impact on your Medicare premiums. It's one of the reasons these decisions belong in a comprehensive retirement income plan rather than being made in isolation.
Where to start
Start with the basic structure — Parts A, B, C, and D — and the fundamental choice between original Medicare plus Medigap versus Medicare Advantage. Then work through the specifics of your situation, ideally with someone who can help you model out the actual costs and make sure you're not missing an enrollment window.
Medicare decisions don't exist in a vacuum — they connect directly to your income plan, your tax situation, and your overall retirement picture. If you'd like help thinking through how they fit together, I'd be glad to be a resource.
The Ready to Retire guide covers healthcare planning as part of a broader look at the financial and personal decisions that come with the transition into retirement.
Download Ready to Retire — A Guide to Entering Your Next Season with Confidence
Or if you'd like to talk through your retirement picture including healthcare costs, you're welcome to schedule a 15-minute intro call.