The 5 Biggest Medicare Mistakes Washington Retirees Make
After working with Washington residents through Medicare enrollment for years, I see the same mistakes come up over and over. Most of them are completely avoidable. Almost all of them are expensive. And several of them are permanent — meaning once the damage is done, there's no way to undo it.
Here are the five I see most often.
Mistake 1: Assuming They Have More Time Than They Do
This is the most common one. Someone turns 65, they're busy, Medicare feels complicated, and they tell themselves they'll deal with it later.
The problem: later has a price tag.
Medicare's Initial Enrollment Period is 7 months long — starting 3 months before your birthday month and ending 3 months after. Miss that window without qualifying employer coverage and you'll pay a 10% permanent penalty on your Part B premium for every 12-month period you were eligible but didn't enroll.
The standard Part B premium in 2026 is $202.90/month. Miss your window by two years and you're paying an extra $40/month — forever. Over 20 years of retirement, that's nearly $10,000 added to your Medicare bills for a deadline you didn't know was real.
What this means in clear terms: The enrollment window isn't a suggestion. It has a hard close date, and the penalty doesn't go away.
Mistake 2: Thinking COBRA Counts as Qualifying Coverage
I hear this one regularly: "I retired early, I'm on COBRA, so I have time before Medicare kicks in."
That's not how it works.
COBRA is continuation coverage from your former employer. It's real health insurance and it works fine for covering your medical expenses — but it does not count as qualifying employer coverage for the purpose of delaying Medicare without penalty.
The moment you leave your job (not when COBRA ends — when you leave), the clock starts on your Special Enrollment Period. You have 8 months to enroll in Part B. If you're on COBRA and waiting until it expires at 18 or 36 months before enrolling in Medicare, you've already missed your window and the penalty applies.
What this means in clear terms: COBRA and Medicare do not have the same timeline. If you retired before 65 and went on COBRA, talk to a Medicare advisor before your 65th birthday — not after.
Mistake 3: Choosing a Plan Based on Monthly Premium Alone
A $0 premium Medicare Advantage plan looks appealing. I understand why. But the premium is only one piece of what a plan actually costs you.
What I see happen: someone chooses the $0 plan, has a health event — a surgery, a cancer diagnosis, a hip replacement — and finds themselves working through $200 copays, multiple specialist visits, and inpatient cost-sharing they didn't anticipate. Their total out-of-pocket for the year hits $6,000, $7,000, $8,000. The $0 premium wasn't actually $0.
A Medicare Supplement Plan G costs more per month — roughly $230–$350 in Washington in 2026. But once you've paid the $283 Part B deductible for the year, it covers nearly everything else. Your total exposure is predictable.
Neither choice is wrong. But the comparison needs to be based on total annual cost — not just the premium line.
What this means in clear terms: Ask not "what does this plan cost per month?" Ask "what is the most I could possibly spend in a bad year on this plan?" That answer is very different depending on the path you choose.
Mistake 4: Never Reviewing the Plan After Enrollment
Most people enroll in Medicare, choose a plan, and never look at it again.
That might be fine. Or it might mean they're paying $40 more per month for the same coverage they could get elsewhere, or that a medication they take every day moved to a higher tier on their Part D formulary, or that their doctor quietly left the plan's network at the start of the new plan year.
Medicare plans can change their premiums, their covered drugs, and their provider networks every single year. The Annual Notice of Change your plan sends in September tells you what's changing — most people toss it without reading it.
In Washington, you have real flexibility during the October 15–December 7 Open Enrollment Period to switch plans. And because Washington uses community rating for Medigap plans, you can shop for a better-priced version of the same Supplement coverage at any time without answering health questions.
What this means in clear terms: A 15-minute annual review can save you money and catch problems before they become surprises. It costs nothing and commits you to nothing.
Mistake 5: Starting on Medicare Advantage Without Thinking About the Exit
This one takes the longest to explain — but it's the one I wish more people understood before they enrolled.
Starting on a Medicare Supplement is flexible. In Washington, you can switch from one Supplement to another at any time without answering health questions. If you're on Plan G with one carrier and find a better price on Plan G with another, you can make that switch.
Starting on Medicare Advantage and wanting to switch to a Supplement later is a different story. Outside of a protected enrollment period, moving from Advantage to a Supplement typically requires medical underwriting. If your health has changed since you enrolled on Advantage, you may not be able to get a Supplement approved at any price.
This isn't a reason to automatically avoid Medicare Advantage. But it's a reason to think carefully about which direction you're starting from — because changing course later may not be an option.
What this means in clear terms: Starting on Supplement and switching to Advantage is easy. Starting on Advantage and switching to Supplement may be impossible. Think about which direction you'd rather have that flexibility in.
A Quick Summary
| Mistake | The Real Cost | How to Avoid It |
|---|---|---|
| Missing enrollment window | Permanent 10% penalty per missed year | Know your 7-month window and act before it closes |
| Thinking COBRA qualifies | Penalty after 8-month SEP window expires | Enroll at 65 regardless of COBRA status |
| Choosing on premium alone | Surprise out-of-pocket costs in a bad year | Compare total annual costs, not just monthly premium |
| Never reviewing the plan | Overpaying, wrong coverage, wrong network | 15-minute annual review every October |
| Advantage without an exit plan | Stuck on Advantage if health changes | Understand the switching rules before you enroll |
Frequently Asked Questions
What is the most expensive Medicare mistake Washington residents make?
Can Medicare mistakes be fixed after enrollment?
How do I find out if I'm making a Medicare mistake right now?
Most of these mistakes are avoidable — but only if you know about them before you enroll, not after. If you have questions about your specific situation, I'm happy to take a look.
Have questions about your specific situation?
Join Michael's free Facebook group — "Turning 65 in Washington State" — where Washington residents get clear Medicare answers without the sales pitch.
Join the group →Michael Gurr is a licensed Medicare and retirement advisor serving Pierce County and Washington State.
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This article is for educational purposes. For official Medicare information, visit medicare.gov.