What are the biggest mistakes people make with Medicare?

[LeEvangeline]

The costliest Medicare errors involve enrollment timing and plan selection. Missing the Initial Enrollment Period results in permanent late penalties. Failing to annually compare Medicare Advantage versus Supplement plans can trap you in unsuitable coverage. A critical oversight is assuming employer coverage allows penalty-free Part B delay; it only qualifies if the employer has 20 or more employees.

Understanding the Initial Enrollment Penalty Your first chance to enroll is the 7-month Initial Enrollment Period (IEP): the three months before, the month of, and the three months after your 65th birthday month. Missing this window for Part B (Medical Insurance) triggers a lifelong penalty. For each full 12-month period you delay enrollment, your Part B premium increases by 10%. This penalty persists for as long as you have Medicare. Data from the Centers for Medicare & Medicaid Services (CMS) indicates that in 2023, the standard Part B premium was $164.90. A 20% penalty would add about $33 monthly, costing an extra $400 annually indefinitely.

Navigating the Medigap Open Enrollment Window If you choose Original Medicare (Parts A & B), purchasing a Medicare Supplement (Medigap) policy is crucial for covering gaps. Your one-time, guaranteed-issue right is the 6-month Medigap Open Enrollment Period. It starts the first month you are both 65 or older and enrolled in Part B. During this window, insurers cannot deny coverage or charge higher premiums based on pre-existing conditions. Missing this period means applying later will require medical underwriting, where insurers can refuse coverage or set premiums based on health status. Industry analyses suggest denial rates for applicants with significant health conditions outside this window can be high.

The High Cost of Not Comparing Plans Annually Medicare plans change yearly. Not reviewing your coverage during the Annual Enrollment Period (October 15 – December 7) is a major financial mistake. Medicare Advantage (Part C) and Part D (drug) plans can alter their formularies, provider networks, and costs annually. A common error is choosing a Medicare Advantage plan based solely on a $0 premium without calculating total out-of-pocket costs. These plans have deductibles, copays, and maximum out-of-pocket limits. A plan with a low premium might have high cost-sharing for your specific medications or frequent doctor visits. Market records show that beneficiaries who switch Part D plans during Annual Enrollment can achieve average annual savings of several hundred dollars on prescription costs.

Critical Rules for Delaying Part B You can delay Part B without penalty only if you have "creditable coverage" from active employment. The rule is precise: the employer or union group health plan must cover 20 or more employees. If you work for a company with fewer than 20 employees, you typically must enroll in Part B when you turn 65 to avoid penalties, as Medicare becomes primary. Failing to understand this specific 20-employee threshold leads to unexpected gaps and lifetime penalties.

Overlooking Essential Part D Enrollment Even if you don't take prescriptions initially, not enrolling in a Part D plan when first eligible results in a late enrollment penalty if you join later. The penalty is calculated by multiplying 1% of the "national base beneficiary premium" by the number of full months you were eligible but didn't join. This penalty is added to your monthly Part D premium for life.

Common Coverage Misconceptions Assuming Medicare is free leads to budget shock. Part A is premium-free for most, but Part B, Part D, and Medigap have costs. Another misconception is that spouses are automatically covered; each individual must qualify based on their own work history or spouse's. Medicare does not cover long-term care, most dental, vision, or hearing aids.

Mistake Category	Specific Error	Typical Consequence	How to Avoid
Enrollment Timing	Missing Initial Enrollment Period (IEP) for Part B	Lifelong 10% premium penalty per delayed year	Mark your 65th birthday timeline; enroll during your 7-month IEP.
	Missing Medigap Open Enrollment Period (OEP)	Subject to medical underwriting; possible denial or higher rates	Enroll in Medigap within 6 months of first signing up for Part B at 65+.
Plan Selection	Not comparing plans during Annual Enrollment (Oct 15-Dec 7)	Higher drug costs, unsuitable network, increased out-of-pocket spending	Use Medicare Plan Finder tool annually to compare your options.
	Choosing a plan based only on premium	Unexpectedly high total costs for drugs and services	Calculate estimated annual total cost including deductibles and copays.
Eligibility Rules	Incorrectly delaying Part B (employer has < 20 employees)	Part B late penalty and coverage gap	Confirm your employer's size. If under 20 employees, enroll in Part B at 65.
	Forgetting to enroll in Part D when first eligible	Lifelong Part D late enrollment penalty	Enroll in a Part D plan during your IEP even if you don't current take drugs.

To navigate these complexities, consult the official Medicare.gov website and consider speaking with a State Health Insurance Assistance Program (SHIP) counselor for free, unbiased guidance.

[VanRebecca]

I learned about the penalty the hard way. I turned 65 but was still on my wife's insurance from her small business—only 15 employees. We thought we were fine. When she retired two years later, I went to sign up for Part B. That's when they hit me with the permanent late penalty. My premium is now 20% higher forever because of that delay. I wish someone had told me the rule clearly: if the company has fewer than 20 people, Medicare needs to be your primary coverage at 65. Don't assume. Call Medicare or your benefits administrator and get the exact size of your employer group in writing.

Another tip from my experience? Don't set your Medicare plan on autopilot. My Advantage plan changed its drug formulary one year, and my regular medication went from a $10 copay to the "non-preferred" tier, costing me $120 per month. I didn't notice until I was at the pharmacy. Now, every October, I block out time to use the Medicare Plan Finder. It's a bit of work, but it saved me over $800 last year.

[MacAnnie]

As a financial planner for retirees, I see two mistakes repeatedly. First, clients fixate on the Medigap Plan F premium without considering Plan G. While Plan F covers the Part B deductible, it's often significantly more expensive monthly than Plan G. For a healthy client, paying that deductible themselves ($240 in 2024) and choosing a lower-premium Plan G usually saves money annually. The math is straightforward: compare the annual premium difference versus the deductible.

Second, there's a dangerous assumption that "my doctor takes Medicare" means they take every Medicare plan. With Original Medicare plus Medigap, that's generally true. But if you choose a Medicare Advantage HMO or PPO, you are locked into a specific network. I've had clients forced to change specialists mid-treatment because they didn't verify network status during enrollment. My professional advice is unambiguous: before finalizing any Advantage plan, contact your key doctors' offices directly. Ask, "Are you in-network for this specific [Insurance Company] Medicare Advantage plan for the upcoming year?"

[Leonard]

Let's clear up three big myths.

Myth 1: "Medicare is free." Part A usually is, if you paid payroll taxes. But Part B costs over $170 monthly for most people. Then add a Part D drug plan and maybe a Medigap policy. Budget for a few hundred dollars per month.

Myth 2: "I'm automatically enrolled." Only if you're already collecting Social Security benefits before turning 65. If not, you must proactively sign up.

Myth 3: "My spouse gets covered under my plan." Nope. Medicare is individual. Your spouse must qualify on their own record—usually by turning 65 or having a disability—and pay their own premiums. There's no family plan.

Getting these basics wrong sets you up for missed deadlines and surprise bills.

[MarcusFitz]

Thinking long-term is where many stumble. The decision between Medicare Advantage and Original Medicare with a Supplement isn't just about this year's costs. It's about future flexibility and healthcare needs.

With a Medigap plan, you pay a higher premium now for predictability. Your out-of-pocket costs are minimal and stable, and you can see any specialist nationwide who accepts Medicare without referrals. This is crucial if you develop a serious condition and need access to top-tier hospitals or multiple opinions.

Medicare Advantage often has lower premiums but functions like an HMO/PPO. Your care is managed within a network. If your health declines and you need frequent, expensive care, hitting the plan's annual out-of-pocket maximum (which can be over $8,000) becomes a real risk. Also, if you start with Advantage and later develop health issues, switching to a Medigap policy is not guaranteed; you'll likely face medical underwriting.

My perspective? If you can afford the Medigap premium, it acts as insurance against catastrophic healthcare costs and provides peace of mind for the future. View it as locking in your health insurance options while you're guaranteed eligible.