Every year, millions of Medicare beneficiaries miss out on hundreds-or even thousands-of dollars in savings because they don’t review their prescription drug coverage. It’s not because they don’t care. It’s because the process feels confusing, overwhelming, and easy to put off. But if you take just a few hours between October 15 and December 7, you can lock in better coverage for the next year, lower your monthly bills, and avoid surprise costs at the pharmacy. This isn’t just about picking a plan. It’s about making sure your medications are covered at the lowest possible price.

Why Annual Review Matters

Your Medicare plan changes every year. Not just a little-sometimes dramatically. A drug that cost $10 last year might jump to $45 this year. Your pharmacy might no longer be in-network. Your plan might add a prior authorization requirement for your insulin. These aren’t rare events. According to CMS, about 60% of Part D plans change at least one medication’s formulary status annually. That means if you didn’t check your plan this year, you’re probably paying more than you need to.

In 2025, beneficiaries who actively compared plans saved an average of $532 on prescriptions alone. Some saved over $1,200. That’s not luck. That’s planning. The biggest reason people overpay? They assume their plan stayed the same. It didn’t.

Know Your Coverage Options

There are two main ways to get prescription drug coverage under Medicare:

  • Original Medicare (Parts A and B) + Part D plan: You get hospital and doctor coverage from Medicare, then add a standalone drug plan. This gives you freedom to see any doctor who accepts Medicare, but there’s no cap on out-of-pocket costs. If you take expensive meds, you could hit the coverage gap (donut hole)-though in 2025, that gap is officially closed thanks to the Inflation Reduction Act.
  • Medicare Advantage (Part C): These plans bundle Parts A, B, and usually D into one. Most include extra benefits like dental, vision, or gym memberships. But they come with strict provider networks. Only 43% of Medicare Advantage plans in 2025 offered out-of-network coverage. If your doctor or pharmacy isn’t in-network, you pay more-or nothing at all.

As of 2024, over half of all Medicare enrollees (32.4 million) are in Medicare Advantage. That number keeps growing. But more people don’t mean simpler choices. In fact, with 738 Part D plans available in 2025, the number of combinations can feel endless.

Step 1: List Every Medication You Take

Before you even look at a plan, get your medication list ready. Write down:

  • The exact name (brand and generic)
  • The dosage (e.g., 10 mg, 25 mg)
  • How often you take it (daily, weekly, etc.)
  • Where you fill it (pharmacy name)

This isn’t optional. If you forget one medication-say, your blood pressure pill or your antidepressant-you might end up with a plan that doesn’t cover it at all. Or worse, it’s covered but only at a much higher cost. People often think they’ll remember, but in October, life gets busy. Write it down. Even if you think it’s simple.

Insulin and GLP-1 drugs like Ozempic are the most common pain points. In 2024, 68% of Medicare helpline calls were about these drugs. The Inflation Reduction Act capped insulin at $35 per month in 2025, but only if your plan covers it. Not all do.

Step 2: Get Your Annual Notice of Change (ANOC)

By September 30, your current plan must send you the Annual Notice of Change. This document tells you exactly what’s changing for 2026: premium increases, new deductibles, formulary changes, pharmacy network updates, and cost-sharing adjustments.

Don’t ignore it. Don’t throw it away. Read it. Highlight every change to your medications. If your plan says, “Lisinopril is now on Tier 4 instead of Tier 2,” that’s a red flag. Tier 4 means higher cost. You might pay $80 instead of $20. That’s $720 extra a year.

Some plans also send an Evidence of Coverage (EOC). That’s the full rulebook. It’s long, but you only need to look at the section about prescription drugs. Focus on the formulary-the list of covered medications-and the cost-sharing rules.

A mech-shaped library displays floating medication cards as a counselor guides an elderly woman through plan options.

Step 3: Use the Medicare Plan Finder Tool

Go to Medicare.gov/plan-compare. This is your most powerful tool. It’s free, official, and updated daily.

Enter your ZIP code, your medications, and your preferred pharmacy. The tool will show you every plan available to you, ranked by total estimated annual cost-not just monthly premium. That’s key. A plan with a $10 premium might cost you $1,000 in drug costs. Another with a $40 premium might cost $300. The tool calculates it all.

Look for:

  • Formulary coverage: Is your drug listed? Is it on a lower tier? (Tier 1 = lowest cost)
  • Cost-sharing: Do you pay a copay or coinsurance? Is there a deductible?
  • Pharmacy network: Is your pharmacy preferred? Preferred pharmacies usually have lower costs.
  • Out-of-pocket maximum: For Medicare Advantage plans, this is capped at $8,000 in 2025. Original Medicare has no cap.

Beneficiaries who used the Plan Finder were 3.2 times more likely to find a lower-cost plan than those who didn’t. That’s not a small edge. That’s life-changing savings.

Step 4: Check Your Pharmacy

Your favorite pharmacy might not be in-network anymore. In 2024, 32% of Reddit users reported their pharmacy was removed from their plan’s network. That means you either pay full price or switch pharmacies.

Call your pharmacy and ask: “Do you accept [Plan Name] as a preferred pharmacy?” If they say no, you’re looking at higher costs. Some plans have two tiers: preferred and standard. Preferred means lower copays. Standard means higher. Don’t assume your pharmacy is still preferred.

If you use mail-order, check if your plan covers it. Some plans offer free shipping or discounts for 90-day supplies. That’s another way to save.

Step 5: Watch for Hidden Restrictions

Just because a drug is on the formulary doesn’t mean you can get it easily. Many plans use:

  • Prior authorization: Your doctor must get approval before the plan pays.
  • Step therapy: You must try a cheaper drug first, even if it didn’t work for you before.
  • Quantity limits: You can only get 30 pills per month, even if you need 60.

These aren’t always obvious. The Medicare Plan Finder doesn’t always flag them. You have to dig into the EOC or call the plan directly. Ask: “Does my medication require prior authorization or step therapy?”

Specialty tier drugs-like those for MS, cancer, or rheumatoid arthritis-are especially tricky. In 2024, 42% of plans increased cost-sharing for these drugs. One beneficiary in Texas paid $1,400/month for her MS med because her new plan moved it to specialty tier. She switched back and saved $11,000 a year.

A figure stands at a crossroads between a dark path and a glowing one, guided by a Medicare-themed mech guardian.

What to Do If You Miss the Deadline

The deadline is December 7. Changes take effect January 1. If you miss it, you’re stuck until next year-unless you qualify for a Special Enrollment Period (SEP). SEPs are rare. They happen if you move, lose other coverage, or enter a nursing home. Most people don’t qualify.

Don’t wait. Start in October. Use the Plan Finder. Call your SHIP counselor. They’re free, certified, and trained to help. There are over 9,400 of them across the U.S.

Common Mistakes to Avoid

  • Only looking at premiums: A $0 premium plan might have a $590 deductible and high copays. Total cost matters more.
  • Ignoring formulary changes: Your drug might be covered-but now it’s Tier 4. That’s a 30-50% price jump.
  • Not checking pharmacy networks: Your CVS or Walgreens might no longer be preferred.
  • Assuming your doctor is still in-network: Especially with Medicare Advantage. 78% of plans changed provider networks between 2023 and 2024.
  • Forgetting about supplemental benefits: Some Advantage plans offer hearing aids or transportation. But eligibility rules are hidden. Read the fine print.

Final Tip: Do It Early

Most people wait until November. That’s when the lines are long, the websites crash, and the phone wait times hit 45 minutes. Start on October 15. Give yourself time. Use the Plan Finder. Compare three plans. Talk to a counselor. Download your ANOC. Print it out. Put it next to your medication bottle.

Medicare isn’t set and forget. It’s a tool. And like any tool, it works best when you use it regularly. The savings aren’t theoretical. They’re real. People are saving hundreds, sometimes thousands, every year by doing this one thing: reviewing their coverage before December 7.

Don’t be the person who pays more because they didn’t check.

What happens if I don’t change my Medicare plan during open enrollment?

If you don’t make any changes, you’ll automatically stay in your current plan for the next year. But that doesn’t mean your costs stay the same. Your plan may increase premiums, raise deductibles, remove your medication from the formulary, or move it to a higher cost tier. You could end up paying hundreds more for your prescriptions without realizing it. Reviewing your plan isn’t about switching-it’s about making sure you’re still getting the best deal.

Can I switch Medicare Advantage plans after December 7?

You can only switch Medicare Advantage plans during one special window: January 1 to March 31. This is called the Medicare Advantage Open Enrollment Period (MAOEP). During this time, you can switch to another Medicare Advantage plan or go back to Original Medicare. But you can’t switch Part D plans during MAOEP. If you’re unhappy with your drug coverage, you have to wait until the next Annual Open Enrollment (October 15-December 7). That’s why it’s critical to get your drug coverage right the first time.

Is there a penalty for dropping Part D coverage?

Yes. If you drop your Part D plan and go without creditable prescription drug coverage for 63 days or more, you’ll pay a late enrollment penalty when you re-enroll. The penalty is 1% of the national base premium ($34.70 in 2024) for each month you were without coverage. That adds up. For example, if you go without coverage for 12 months, your penalty will be $4.16 extra per month-forever. Only drop Part D if you’re switching to another plan that includes drug coverage or if you have other creditable coverage (like from an employer).

How do I know if my medication is covered?

Check the plan’s formulary, which is a list of all covered drugs. You can find this on the Medicare Plan Finder tool by entering your medications. The tool will tell you if your drug is covered, on which tier, and what your cost will be. You can also call the plan directly and ask: “Is [medication name] covered? What tier is it on? Are there any restrictions like prior authorization?” Always verify with the plan, not just the website.

Do I need to enroll in Part D if I take no medications?

If you truly take no prescription drugs, you don’t need Part D. But consider this: What if you need a new medication next year? A broken bone, an infection, or a sudden diagnosis could require a drug you didn’t expect. Without Part D, you’ll pay full price. And if you wait to enroll later, you’ll pay a late penalty. Many people choose a low-cost Part D plan-sometimes under $10/month-even if they don’t take drugs now. It’s cheap insurance against future costs.