Every year, Medicare eligible Californians face a dizzying array of choices. Between the television commercials flooding our screens during enrollment season, the mail overflowing with plan information, and the confusing rules about deadlines and penalties, it's easy to make decisions you later regret. We've helped thousands of California seniors navigate this process, and we've seen the same mistakes pop up again and again. The good news? They're completely avoidable if you know what to watch for.
Mistake #1: Not Reviewing Your Plan Every Year
This is perhaps the most common mistake we see. Many people think, "I've got Medicare figured out now, so I'll just stick with my plan." But here's the thing: plans change every single year. Coverage areas shift. Provider networks expand or contract. Formularies get updated. Copays and deductibles change. Even if you're perfectly happy with your plan today, it might be completely different next January 1st.
What to do instead: Mark your calendar for October. Every October, sit down with your current plan documents and compare them to new options available in your area. You can use Medicare.gov's plan comparison tool, or reach out to a free licensed agent (like our team) to help you compare apples to apples. Even if you decide to stay with your current plan, you've made an informed choice based on current information.
Mistake #2: Choosing a Plan Based Only on Premium
You see the $0 premium Medicare Advantage plan and think you've found the deal of the century. Zero dollars a month? That must be the best option, right? Not necessarily. A $0 premium might come with $50 copays at every doctor visit, a limited drug formulary, or a very narrow network that doesn't include your preferred doctors.
Premium is just one piece of the puzzle. A plan that costs $100 per month but has $10 copays and includes all your doctors might save you thousands of dollars compared to a $0 plan with high out-of-pocket costs.
What to do instead: Look at the total cost of care, not just the premium. Calculate copays for your typical doctor visits. Add in your expected prescription costs. Check if your doctors are in-network. Then compare the total annual expense across plans. The lowest premium rarely equals the lowest total cost.
Mistake #3: Not Checking If Your Doctors Are In-Network
Doctor networks change constantly. A physician who was in-network last year might have left the plan—or even retired—this year. If you automatically enroll in the same plan without checking, you could lose access to your primary care doctor, your cardiologist, or your specialist.
This is especially important in California, where there's so much physician movement between practices and networks.
What to do instead: Before enrolling in any Medicare Advantage plan, verify that your current doctors are in-network for the coming year. Most plans have online directories where you can search by doctor name. If your preferred doctor isn't listed, call the plan directly to confirm. If a key doctor isn't in-network, seriously reconsider that plan.
Mistake #4: Ignoring the Drug Formulary
A formulary is the plan's list of covered medications. Your arthritis medication might be covered. Your blood pressure medication might be on it too. But your cholesterol medication? That might require prior authorization, or it might be on a higher cost tier, or it might not be covered at all. Or worse, it might have moved to a higher tier from last year, meaning you'll pay more out of pocket.
If you don't review the formulary before enrolling and your medication isn't covered, you're in for an unpleasant surprise at the pharmacy.
What to do instead: List every medication you take, including doses. Then search for each one in the plan's formulary. Make note of the tier (Tier 1 = cheapest copay, usually generics; higher tiers = more expensive). If a critical medication is on Tier 3 or 4, or not covered, ask yourself if the plan's other benefits are worth the higher drug costs. Talk to your doctor, too—sometimes they can prescribe an equally effective medication that's on a lower tier.
Mistake #5: Missing Enrollment Deadlines
Miss the deadline to enroll in Medicare? There's a late enrollment penalty that you'll pay for the rest of your life. Miss your plan's deadline to add or change coverage? You might be stuck with your current plan for a whole year. It sounds dramatic, but enrollment deadlines are no joke.
California's volume of Medicare enrollment information during Open Enrollment season can actually make this mistake more likely—so much mail and so many commercials that the actual deadlines get lost in the noise.
What to do instead: Write the dates down right now. For 2026, Medicare Open Enrollment is October 15 – December 7. Mark it on your calendar. Set a phone reminder. Tell a family member so they can help you remember. Enrolling early is fine—you don't need to wait until December. In fact, earlier is often better since you avoid the rush and get answers to questions more quickly.
Mistake #6: Falling for Medicare Scam Calls
Your phone rings. The caller says they're from Medicare and they're calling to update your information. They mention a new benefit you might qualify for. They use high-pressure sales tactics. They want your Medicare number right away.
This is a scam. Medicare doesn't cold-call you. Medicare-licensed insurance agents might call you if you've requested information, but legitimate agents don't use aggressive pressure or rush you.
California sees more Medicare telemarketing than most states, partly because of the size of our senior population. That means scammers also target California heavily.
What to do instead: Hang up on unsolicited Medicare calls. If you want information about plans, you contact them—they don't call you. If someone calls claiming to be from Medicare offering a "special deal," it's not real. Instead, go to Medicare.gov directly, call 1-800-MEDICARE, or contact a trusted licensed agent in your area who can help without pressure.
Mistake #7: Not Asking for Help
You think you need to figure this out alone. You think asking for help is a sign of weakness. You think licensed Medicare agents are just trying to sell you something.
Here's the truth: free, licensed Medicare counseling exists for exactly this reason. California's State Health Insurance Assistance Program (called HICAP—Health Insurance Counseling and Advocacy Program) offers completely free Medicare counseling to seniors. They have no financial incentive to steer you toward any particular plan. They exist to help you understand your options.
And yes, there are licensed agents (like our team) who do earn commissions when you enroll in a plan. But that commission is paid by the insurance company, not by you. There's no added cost to you for getting professional help. If anything, the right guidance can save you thousands in unnecessary medical expenses.
What to do instead: Ask for help. Call HICAP. Reach out to a licensed agent. Ask your doctor's office—they often know which plans cover their practice. Talk to family members who are on Medicare. You don't have to make this decision in isolation, and you're not supposed to. That's why these resources exist.
The Bottom Line
Medicare enrollment mistakes are common because the system is genuinely complex. But they're also completely preventable. By reviewing your plan annually, looking beyond premium, checking your doctors and drugs, meeting deadlines, avoiding scams, and asking for help when you need it, you set yourself up for good Medicare coverage that actually works for you.
The goal isn't to find the "best" plan in some abstract sense. The goal is to find the best plan for your specific situation—your doctors, your medications, your health care needs, and your budget. That's a personalized decision, and it's worth getting right.