What the window is and how much is left
Medicare's Annual Enrollment Period runs from October 15 to December 7 every year, according to CMS and Medicare.gov. If you are reading this on Saturday, October 31, that leaves 37 days, counting from the 31st to the 7th of December. That is about five weeks, and it passes faster than most people expect because the final week tends to be crowded with other obligations. The reason the date matters is simple: this is the main yearly window in which you can change how your Medicare coverage works without needing a special qualifying event. Whatever you choose and confirm by December 7 generally starts on January 1, per Medicare.gov. So the real deadline for a calm decision is earlier than the official one, because you need time to compare plans, ask questions, and correct anything that looks wrong. Think of December 7 as the last day to act, and of mid-November as a sensible day to finish. Here is what is open to you.
What you can change before December 7
During AEP, you can make several kinds of changes, according to Medicare.gov. If you have Original Medicare, you can switch to a Medicare Advantage plan. If you have Medicare Advantage, you can switch to a different Medicare Advantage plan or return to Original Medicare. You can also join a Part D prescription drug plan, switch to a different one, or drop drug coverage entirely, although dropping it carries risks covered later. Each of these is a separate decision, and people often treat them as one. Your drug plan is a different choice from your medical coverage, and a plan that looks good on premiums may cover your medications poorly. Use the Plan Finder tool on Medicare.gov, enter your exact medications and doses, and pick your pharmacies. The tool then shows estimated total costs for the year rather than only the monthly premium. AEP does not guarantee you can buy a Medigap policy, because insurers in most states may ask health questions.
When changes take effect, and what doing nothing means
Plan changes made during AEP generally begin January 1, according to Medicare.gov. That means your current coverage continues through December 31, and you do not lose protection in between. It also means there is a gap of roughly three and a half weeks between the December 7 deadline and the start date, which is where surprises tend to surface. Insurers send ID cards, welcome packets, and sometimes pharmacy notices in that stretch. If you wait until the last days to enroll, you have little time to confirm that your doctors and pharmacy are in the new plan's network or to fix an error. Doing nothing is also a decision. If you stay in your current plan, you accept whatever that plan has changed for next year, including its premium, deductible, drug list, and provider network. Plans send an Annual Notice of Change in the fall describing these shifts. Reading that notice is the cheapest way to learn whether staying put makes sense for you.
A worked example: comparing two drug plans
Here is a hypothetical example with made-up numbers, so you can see the method. Suppose Dana takes three medications and is comparing two drug plans in Plan Finder. Plan A has a $15 monthly premium and Plan Finder estimates her drug costs at $900 for the year. Plan B has a $0 monthly premium and estimates her drug costs at $1,500. First, convert the premium to a yearly figure: $15 times 12 months equals $180. Add that to the drug estimate: $180 plus $900 equals $1,080 for Plan A. Plan B's premium adds nothing, so its total is $1,500. Plan A costs $420 less over the year, even though Plan B looks cheaper each month. Now Dana runs one more check: her pharmacy. If her regular pharmacy is out of network for Plan A, she must either switch pharmacies or pay more, and the estimate changes. The lesson is to compare total yearly cost with your actual drugs and pharmacy, not the premium alone.
What people get wrong
Several mistakes repeat every year, and each costs real money. The first is assuming last year's plan is still the best one; premiums, drug lists, and networks can change, and KFF publishes analyses of prior authorization in Medicare Advantage. The second is dropping Part D because you take no medications right now. Medicare.gov explains that going without creditable drug coverage can bring a late enrollment penalty that is added to your monthly premium for as long as you have Part D, so a small saving today can become a permanent charge. The third is switching from Original Medicare to Medicare Advantage without checking whether your doctors and hospitals are in the plan's network. The fourth is believing a Medigap policy is guaranteed if you later return to Original Medicare. The fifth is waiting for the final days, when a mistake leaves almost no time to correct it. Each of these is avoidable with a short check done now. Checking early leaves time for questions.
How to check your own situation
Gather four items and spend an hour with them. First, your current plan's Annual Notice of Change, which lists next year's premium, deductible, and coverage changes. Second, your medication list with exact names, doses, and how often you fill them, plus the pharmacies you use. Third, a list of your doctors and hospitals. Fourth, your Medicare card and, if you have one, your Medigap policy details. Then open Plan Finder on Medicare.gov, enter your medications and pharmacies, and compare yearly totals as in the example. Ask each plan whether your doctors are in network, whether any of your drugs need prior authorization, and what the out-of-pocket limit is. If your income is limited, check Extra Help through the Social Security Administration, and ask about the Medicare Prescription Payment Plan described by CMS, which lets you spread drug costs across the year. Free, unbiased help is available from your State Health Insurance Assistance Program at shiphelp.org. Their counselors do not sell plans.
This newsletter is general educational information, not personalized insurance, legal, or financial advice. Plan availability, costs, and rules vary by location and change each year; confirm details at Medicare.gov or with your State Health Insurance Assistance Program.