I talk to a lot of 65-year-olds, and one of the biggest fears they have is making a mistake with Medicare . It’s hard not to be afraid when you keep hearing well-intentioned, but conflicting advice such as:
“You have to sign up for Medicare at 65.”
“You don’t have to sign up for Medicare at 65.”
“You can change your Medicare insurance every year.”
During my 20-plus years as a retirement-focused financial adviser, I’ve just about heard it all — some true, some false and just about all of it leaving near-65-year-olds wondering how they can figure it out in time.
Below are the five most common mistakes retirees make with Medicare and what you can do to try to avoid them.
What makes Medicare so different
Your health insurance choices used to be easy. Your work gave you two or three options and you chose the one that fit your family best.
Then you turn 64 and you get bombarded with advertisements in the mail touting how great a particular Medicare insurance plan is.
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When I checked Medicare.gov’s Plan Comparison Tool in September 2026, there were 81 different options near me in Wisconsin: 39 Medicare Advantage plans, 10 prescription drug plans and 32 supplement insurance ( Medigap ) options.
The number and types of plans available to you will depend on where you live.
With so much information and so many different plans, it’s no wonder Americans keep making these five common mistakes.
Mistake No. 1: Assuming Medicare is automatic
Medicare feels automatic since many people enroll or get signed up for it at 65, but that feeling of “automatic” often turns into “I don’t have to think about it” — and that’s a big mistake.
Medicare enrollment generally is automatic if you’ve already been receiving Social Security retirement benefits for at least the four months before age 65. A few months before your 65th birthday, you’ll get your Medicare card in the mail showing that you’re enrolled for Part A and B .
If you have current employer-provided health insurance from a company with 20-plus employees, you may be able to delay starting Part B. Before you do, check with your employer to find out how your health coverage coordinates with Medicare.
If you’re signed up for Part A and B automatically, that doesn’t mean you automatically get signed up for other private Medicare insurance to pay for the gap between what Medicare covers and what Medicare pays.
You should still evaluate whether you’re better off with Medicare Advantage or original Medicare with Medigap (supplemental) insurance — and you’ll have to proactively sign up to get those coverages.
Mistake No. 2: Misunderstanding what counts as ’employer coverage’
Many people turning 65 think, “I don’t need to sign up for Medicare. I already have insurance through my employer.” It turns out they actually have retiree coverage, COBRA or even TRICARE from prior military service.
Retiree health insurance and COBRA plans are not coverage from your current employer. And TRICARE states that you need Part A and B to get TRICARE For Life .
If you have employer-provided health insurance based on your or your spouse’s current employment with a company of 20-plus employees, you may be able to delay signing up for Medicare. That’s true, and yet there’s so much confusion around that.
Your “employer coverage” must be from active, current employment.
Retiree healthcare doesn’t count as current employer coverage that could allow you to delay Part B. COBRA generally doesn’t count either.
TRICARE states , “If you’re eligible for both TRICARE and Medicare Part A, then in most cases, you must have Medicare Part B to keep TRICARE.” (Emphasis added.)
Mistake No. 3: Confusing the different Medicare parts and choices
Medicare lists four different parts of Medicare, along with optional Medigap insurance, and points out the differences between Medicare and Medicaid . With similar names and so many parts, no wonder it’s confusing.
Medicare Part A (hospital insurance) covers inpatient care in hospitals, skilled nursing facility care, hospice care and home healthcare.
Most people get Part A with no premium cost because they, or their spouse, qualified by working and paying Medicare payroll taxes for “40 quarters” — basically 10 years. Premium-free doesn’t mean cost-free though. You can still have deductibles, copays and other out-of-pocket costs.
Medicare Part B (medical insurance) helps pay for doctor visits, outpatient care and preventive care, such as screenings, shots or vaccines, and yearly “wellness” visits.
Part B costs $202.90 a month , which is often a surprise to many retirees who think it’s free. It can cost even more if you have a high enough income and must pay Income-Related Monthly Adjustment Amount (IRMAA) surcharges.
Medicare Part D helps cover the cost of prescription drugs.
Drug coverage is often part of a Medicare Advantage plan. But if you choose a Medicare Supplemental Insurance (Medigap) plan , you’ll generally buy part D drug coverage separately, unless you have other creditable drug coverage.
Medicare Supplement Insurance (Medigap) helps you pay your share of the costs of original Medicare.
People often ask me, “What does Medicare Supplement cover?”
My answer is, “Medicare Supplement generally covers what Medicare covers, but it generally pays for many of the costs that Medicare makes you responsible for.”
Medicare Part A has deductibles, coinsurance and copays that you are responsible for.
Medicare Part B has a deductible, after which you generally pay for 20% of the cost of the Medicare-approved amount for services Medicare covers.
That’s where Medicare Supplement (Medigap) comes in, to help pay the costs of your healthcare that Medicare covers but doesn’t fully pay. You could also choose a different route, called Medicare Advantage.
Medicare Advantage (also known as Part C) is an alternative to original Medicare. You get a “bundled” plan through a private insurance company that is Medicare approved and essentially brings your Part A, Part B and usually Part D coverages all together.
Many Medicare Advantage plans have low or even $0 monthly plan premiums, while Medigap policies generally charge a separate monthly premium.
However, those on Medicare Advantage generally must continue paying their Part B premium, along with deductibles, copayments and specific provider networks.
Mistake No. 4: Ignoring the potential extra costs of Medicare through IRMAA
Many people are surprised that Medicare Part B has a monthly premium. They expect the taxes they paid throughout their career to cover their Medicare in retirement.
What’s even more surprising is when your income from two years ago causes you to pay extra for Medicare through the IRMAA.
I met a client recently who was upset that his Medicare premiums were higher this year than last year.
I discovered he had retired two years ago. His income from that year was high enough to go over the IRMAA threshold so that both his and his wife’s Medicare premium was roughly double the normal amount.
Fortunately, you can appeal your extra Medicare costs through IRMAA, and “work stoppage” is one of the “life-changing” events Social Security will take into account.
My client had retired, and his income is now lower. So after the couple requested a new IRMAA determination based on his retirement and their reduced income, their combined Medicare premiums were reduced by roughly $5,000 for that year.
This client’s IRMAA surcharge highlights how interconnected all the pieces of retirement are. Your added income in one year, from working or perhaps Roth conversions or stock sales, can affect your healthcare costs two years later.
Retirement isn’t just about your Medicare decision and your investment decision, and your Social Security decision separately. It’s about how each of these areas affect each other.
That’s why I created a five-step retirement master plan to help all the pieces of retirement fit together, which you can find in my book Retire Today .
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Mistake No. 5: Not re-evaluating your Medicare Advantage or drug plan each year
Each year during open enrollment from October 15 through December 7, I send a message to my clients encouraging them to review their Medicare Advantage or prescription drug plan for the following year.
By far, the most common response is, “Nothing changed for me this year, so I don’t need to do this.”
But here’s the thing: Something may have easily changed. Your existing plan could have changed quite a bit.
Every year, your Medicare Advantage or Part D drug plan can change its cost, its network, its preferred pharmacy, its benefits, its provider list.
And even if your plan doesn’t change one thing, all the other plans could change and you might be missing out on a better plan for you.
You may find another plan that better fits your healthcare needs, or your prescription drugs, providers and budget.
Whether you’re on Medicare already, or getting ready for Medicare, follow these five steps to avoid big Medicare mistakes:
File for Medicare at the right time
Confirm how your current health insurance coordinates with Medicare
Learn the different parts of Medicare and what they cover
Understand how past income affects current Medicare costs — and whether you qualify for a reduction in those costs
Re-evaluate your Medicare Advantage and drug plan options each year
Take these five steps before, and even after, you file for Medicare, and you’ll feel much more confident in the Medicare decisions you make.
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Jeremy Keil is an Investment Adviser Representative of Alongside, LLC, d/b/a Keil Financial Partners, an investment adviser registered with the SEC. This article is for general information and education only and is not individualized investment, legal, or tax advice. Investing involves risk, including possible loss of principal. Medicare rules, premiums, plan availability and coverage provisions may change and can vary based on individual circumstances and location. Readers should confirm current information with Medicare, Social Security, their benefits administrator, or an appropriately qualified insurance or Medicare professional before making coverage decisions. Kiplinger does not endorse the author’s views, products, services, or strategies, and publication by Kiplinger does not constitute an endorsement, recommendation, or guarantee of any kind. For more about Alongside LLC, see its Form ADV at the SEC’s Investment Adviser Public Disclosure website.
This article was written by and presents the views of our contributing adviser, not the Kiplinger editorial staff. You can check adviser records with the SEC or with FINRA .
