Whether you’re the helpdesk for your parents or you’re coming up on your own retirement, there are a few Medicare surprises that often catch people off guard.
Here's the thing nobody tells you: most people don't learn about Medicare from a class or a pamphlet. They learn it from someone who already went through it — usually after making a mistake first.
Consider this your head start. Here are five things about Medicare that don't come up until you need them.
Turning 65 doesn't mean automatic enrollment
Here's the first surprise: unless you’re already collecting Social Security, Medicare doesn't sign itself up. Signup has to happen during a specific window, three months before to three months after your 65th birthday.
For those who miss this window, a penalty gets added to their monthly premium for as long as they have Part B (Part B is the part of Medicare that covers things like doctor visits, outpatient care, preventive services and equipment).1 Depending on when they enroll, this monthly penalty could go on for decades. It's a quiet rule with a permanent consequence, and it's the single most common thing people wish someone had told them sooner.
Original Medicare doesn't cover dental, vision or hearing
This detail catches almost everyone off guard. Original Medicare covers hospital stays, doctor visits and a lot of medical care. It does not cover routine dental cleanings, a new pair of glasses or a hearing aid.2
For a lot of retirees, that turns into substantial out-of-pocket expenses at the point in life when their income diminishes. It's also exactly the kind of gap many Medicare Advantage plans are built to close. Original Medicare leaves room for coverage you add to fit your needs.
There's no cap on out-of-pocket costs
Most insurance has a maximum amount you’re required to pay, beyond which the coverage takes over completely. Original Medicare doesn't work that way. Without added coverage, there's no yearly maximum on what a Medicare patient could end up paying.3
That's not a reason to panic. Supplemental coverage puts a ceiling back in the picture. Once you know the gap is there, closing it is the easy part.
Working past 65 changes the math
If you're getting close to 65 and trying to think about the best age to retire, the "right" age isn't the same for everyone. One deciding factor almost nobody thinks to ask about is how many people work at the company.
At a small employer (fewer than 20 employees) Medicare usually becomes the primary coverage, even if the employee stays on the group plan. At a larger employer, the group plan typically stays primary, and Medicare can wait without any penalty.4 Two people can retire from the exact same job title at two different companies and need to make opposite decisions. It's worth checking before assuming either way.
High earners pay more for their Medicare
Your income still matters while on Medicare.
Most do not know that their Medicare premiums are tied to their income from two years ago. Medicare uses your adjusted gross income from two years prior to determine if you are subject to the “Income-Related Monthly Adjustment Amount” (IRMAA). This assessment happens each new year, so depending on any changes in your income, you could have to pay more for your Part B and Part D premiums.
This is very important for those who take a large distribution from their retirement accounts or inherit money from a family member.
When can you make changes?
The Annual Enrollment Period is from October 15 to December 7. This is your window to make changes, enroll or disenroll from a Medicare Advantage plan or Part D Prescription Drug plan for the next calendar year. If you are on a Medicare Supplement (aka Medigap) plan, each state has its own rules on when, or even if, you can make a guaranteed change to your coverage. Otherwise, you may have to qualify medically to change Medicare Supplement plans.5
You don't have to be an expert in this
That's the point of your local Highstreet agent. Medicare is full of rules that only seem to matter once you've already made a decision without understanding the rules, and there's no reason to figure it out alone.
If any of this raised a question, talk to a local Highstreet agent. We’re here for your parents, your spouse and you when the time comes to plan for Medicare.
Highstreet Insurance & Financial Services is licensed and certified to offer Medicare Advantage (Part C), Medicare Supplement, and Medicare Prescription Drug Coverage (Part D). We do not offer all plans in all areas. Any information we provide will be limited to those plans we do offer. For more information on all your plan choices, please contact 1-800-MEDICARE or Medicare.gov. Not affiliated with or endorsed by the Federal Medicare Program and any Government entity.
Sources
- Medicare.gov (n.d.). Avoid late enrollment penalties. https://www.medicare.gov/basics/costs/medicare-costs/avoid-penalties
- Medicare.gov (n.d.). Your coverage options. https://www.medicare.gov/basics/get-started-with-medicare/get-morecoverage/your-coverage-options
- National Council on Aging (2026). What You'll Pay in Out-of-Pocket Medicare Costs in 2026. https://www.ncoa.org/article/what-you-will-pay-inout-of-pocket-medicare-costs-in-2026/
- Centers for Medicare & Medicaid Services (2024). Medicare Secondary Payer. https://www.cms.gov/medicare/coordination-benefits-recovery/overview/ secondary-payer
- Kiplinger (2026). The Rules for Making a Medigap Switch. https://www.kiplinger.com/retirement/medicare/604483/the-rules-formaking-a-medigap-switch