Medicare's annual Open Enrollment Period began Oct. 15 and lasts until Dec. 7. If you're under 65, that's pretty irrelevant to you. But if you're already on Medicare or are eligible to sign up, you should circle those two dates on your calendar -- even if you're happy with your current health insurance provider.

For most seniors, this is the only chance they get to make changes to their insurance plan for a whole year. So it's worth finding a few minutes to do the following four things.

Smiling person relaxing on couch while looking at laptop.

Image source: Getty Images.

1. Review your needs

Your health situation can change a lot in one year, and that can affect the type of coverage you need and the plan that's right for you. So take stock of any new health conditions that have arisen recently. Look at the coverage your current insurance plan offers for any necessary treatments and decide whether that's sufficient for you.

Think about your budget as well. Original Medicare has fixed premiums and deductibles, but even after you've met your deductible, you'll still have a co-pay. Those who frequently visit the doctor could end up paying a lot out of pocket with an Original Medicare plan, which has no yearly out-of-pocket limits. In this case, a Medicare Advantage plan, which has limits, could be a wiser choice.

Medicare Advantage plans offer all the same coverage as Original Medicare as well as some extra protections. They're available through a variety of health insurers. But they come with their own set of restrictions, including provider networks that limit who you can see.

2. Review Medicare's 2023 changes

Every year, the government makes small adjustments to the Medicare program's cost and coverage. It's wise to familiarize yourself with these so you know what your plan does and doesn't cover, and you aren't met with any surprises when you get your bills.

Some of the biggest coverage changes for 2023 include:

  • Coverage for lung cancer screenings for qualifying individuals
  • Additional coverage for immunosuppressive drugs for those who have had a kidney transplant
  • Changing start dates for new Medicare beneficiaries

And then there's the premium change. Medicare Part B costs are actually going down slightly for 2023. Premiums will drop from $170.10 each month for most seniors to $164.90 per month. The Part B deductible will fall from $233 to $226. So seniors might have a little more wiggle room in their budgets.

3. Shop around for better plans

Set aside some time to review all the Medicare plans available to you to decide which one makes the most sense. You can view your options on Medicare's website. Don't base your decision on price or coverage alone. Consider the following factors:

  • Costs: premiums, deductibles, and co-pays
  • Coverage
  • Prescription drug coverage
  • How it fits with any other health insurance plans you already have (for example, Medicare supplement plans, employer-sponsored health insurance, or tribal health insurance)
  • Whether your preferred doctors are part of your plan's network (Medicare Advantage only)

You might not find a plan that checks every box off your list. But you can go with the one that has the most features you're looking for right now.

4. Consider ways to fill in the gaps

Original Medicare leaves a lot of gaps that could lead to large out-of-pocket bills for seniors. Dental care, vision care, and hearing aids aren't covered, so seniors who want help with these bills will need to either consider a Medicare Advantage plan or some other sort of supplemental coverage.

You could also look into dental or vision discount programs. These aren't insurance, but they can help you save on your costs anyway. You pay a monthly fee to participate in the program, and then the program gives you access to discounted rates at many dental and vision providers. It's up to you to decide if these services are worth it. But you should have some sort of plan for how you'll handle these costs so you don't have to drain your retirement savings prematurely.

After all this, you might decide the plan you already have is still the best choice for you, and that's fine. Just be sure to make your final decision before Dec. 7 or you'll have to wait another year.