AEP 2026 — the Medicare Annual Enrollment Period — runs from October 15 through December 7, and whatever you choose during this window takes effect January 1, 2027, the start of Plan Year 2027. With a few weeks still on the clock, this is exactly the point in the season when rushed decisions start to happen. People either put off their review until the last few days, or they make a quick change without double-checking the details, and end up locked into a plan that doesn’t actually fit for the next year. Below are seven mistakes that come up again and again during AEP, along with what to do instead while there’s still time to fix them.
Mistake 1: Assuming Your Plan Is Staying the Same
Medicare Advantage and Part D plans are allowed to change their premiums, deductibles, provider networks, and covered drugs every single year. Nothing requires your plan to stay exactly as it was, even if you take no action at all. The plan you’re happy with today could look different on January 1 simply because the insurance company redesigned it, not because you did anything wrong. If you skip your annual review entirely, you won’t find out about a dropped doctor or a pricier medication until you’re already using the new plan year’s coverage — which is too late to change anything until spring. Our AEP 2026 guide walks through what to check and when.
Mistake 2: Skipping the ANOC
Every fall, your current plan mails an Annual Notice of Change (ANOC), usually by the end of September. It spells out exactly what’s different for Plan Year 2027 — new premium, new deductible, network changes, and any drugs moving to a different cost tier. Many people set this letter aside without reading it, assuming it’s routine paperwork. It almost never is. If you’ve misplaced yours, you can usually find a digital copy on your plan’s member website or by calling the number on your member ID card. Our guide on how to read your ANOC breaks down the sections that matter most.
Mistake 3: Not Checking Your Doctors and Pharmacy Are Still In-Network
Medicare Advantage plans use provider networks, and those networks change yearly. A doctor, specialist, or pharmacy that was in-network this year isn’t guaranteed to stay in-network for 2027. If you don’t confirm this before December 7, you might not find out until you try to schedule an appointment and learn you’re now out-of-network, facing a much higher bill or needing to switch providers altogether. Call your doctor’s office directly and ask which plans they’ll be accepting for 2027 — don’t rely only on the plan’s own online directory, since those can be out of date. See our post on checking your network and pharmacy before AEP for a step-by-step approach.
Mistake 4: Comparing Premiums Only, Not Total Costs
A $0 premium plan can look like the obvious winner, but premium is only one piece of what you’ll actually spend over a year. Deductibles, copays, coinsurance, and the plan’s out-of-pocket maximum all affect your real cost, especially if you end up needing more care than expected. The same logic applies to Part D: a plan with a low premium might place your specific medications on an expensive tier, while a slightly higher-premium plan covers them more cheaply overall. For context on where current Medicare costs stand, see our 2026 Medicare costs guide — and always check the specific plan’s Summary of Benefits rather than assuming costs carry over unchanged into 2027.
Mistake 5: Ignoring Star Ratings and Plan Quality
Medicare assigns star ratings, from 1 to 5, based on member satisfaction, customer service, and care quality, and these ratings change from year to year. A plan that was highly rated two years ago may have slipped, and a once-average plan may have improved. Star ratings aren’t the only factor that matters, but they’re a useful quality check that many people skip entirely when comparing options. Our post on Medicare Advantage star ratings explains what the ratings measure and how much weight to give them.
Mistake 6: Not Reviewing Your Part D Formulary
If you take any prescription medications, the plan’s formulary — its list of covered drugs and what tier each one falls into — deserves its own careful look. Formularies change every year, and a drug that was covered at a low copay this year could move to a higher tier, require prior authorization, or drop off the list for 2027 entirely. Running your specific medications through the plan’s formulary tool before you enroll, rather than after, can save a frustrating and expensive surprise in January. Our guide on reviewing your Part D formulary before AEP covers exactly how to do this.
Mistake 7: Waiting Until the Final Days to Decide
AEP gives you nearly two months, but a large share of changes get submitted in the final week before December 7. Waiting that long leaves little room to fix a submission error, get a question answered, or back out if you change your mind — and if something goes wrong with your enrollment right at the deadline, there’s no buffer left to correct it before January 1. The good news is that Medicare allows unlimited changes during AEP; only your last submission before the deadline counts. That means there’s no downside to enrolling early and then adjusting later if something changes, versus waiting and hoping everything goes smoothly at the last minute.
None of these mistakes are complicated once you know to look for them — they mostly come down to not reviewing something before the deadline passes. If you’re not sure where to start, our basics page and enrollment overview are good places to refresh the fundamentals, and the glossary can help with any unfamiliar terms along the way. With a few weeks still left in AEP 2026, there’s time to compare your options properly instead of guessing.
Have questions? Kayla Price is a licensed insurance agent serving NC, SC, GA, FL, VA, MD, MI, KS, TX, and OH. Call (866) 648-1578 or visit priceservicesgroup.com.