If you're 65 or older and eligible for Medicare, it's time to look at your plan for next year. The open-enrollment period runs from Oct. 15 through Dec. 7, and if you want to make changes to your plan, this is your chance.

During the open-enrollment period, you can switch from Original Medicare to a Medicare Advantage plan (or vice versa). You're also able to switch to a different Advantage plan at this time, or if you have Medicare Part D coverage, you can switch to a different Part D plan. If you missed your chance in the past to enroll in Part D coverage, you can also enroll now during open enrollment (though you might face a penalty for late enrollment).

Medicare enrollment form

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If you don't want to make any changes to your plan, you don't need to do anything right now. However, even if you want to stay with the same plan, your coverage and premiums could change for the next year. The plans that are available change from year to year, so there could be a better option out there now. It never hurts to review your current coverage and the other plans available to see whether you could get a better deal elsewhere.

It's not always easy wading through dozens of different plans and weighing your options, but it's necessary if you want to be sure you've chosen the right plan for you. Healthcare is one of the biggest expenses you'll face in retirement, and choosing the wrong plan could cost you thousands. To ensure you're choosing the best option, here are three steps you can take:

1. Estimate the type of healthcare coverage you'll need in 2019

You can't always predict what types of health issues will arise over the next year. But you can estimate the type of coverage you'll need based on your current health and the type of medical care you've received in the past.

For example, if you know you're going to be taking certain prescription drugs, you may need a Medicare Part D plan or an Advantage plan that includes prescription drug coverage. Likewise, if you were recently diagnosed with a health issue that requires a visit to a specialist's office, it might be a good idea to have a plan that will cover that.

This is also a good time to review all your doctor visits over the last year to get a snapshot of the medical care you've received -- it's easy to forget about these visits over the course of a year. And be sure to include everything from vision appointments to specialist visits to general checkups. Then use that snapshot as a gauge for what 2019 will look like in terms of healthcare. You might expect it to be similar to 2018, or you could estimate that you'll have more or fewer doctor visits over the coming year.

2. Review all your plan options and compare costs

Once you have an idea of the type of medical care you'll need, it's time to start comparing plans. The best place to start browsing is Medicare.gov's Plan Finder. You can enter your ZIP code to see the available plans in your area, enter information about your current plan and coverage, and see all your options.

You also can filter your results based on the monthly premium, annual deductible, and coverage options. You can even search for plans that cater to those with disabilities or who need long-term care.

Once you've narrowed your list of available plans, you'll be able to see a side-by-side comparison of your current plan and the other options available. Here, you can compare variables such as monthly premiums, annual deductibles and prescription drug co-pays and co-insurance, out-of-pocket spending limits, and estimated total costs per year.

Remember that cost isn't the only factor to consider, and just because a plan is cheaper doesn't necessarily mean it's better. The Plan Finder also includes the average customer rating for each plan, which can give you a good idea of the type of customer service to expect. Sometimes it might be worthwhile to pay more for a plan with stellar customer service than take a risk with a less expensive plan that could result in a year filled with frustration.

3. Make sure your doctors are covered

Even if you're not planning on switching plans, in-network providers can change each year, so be sure to check that your favorite doctors and hospitals are still covered under your plan. If you're changing to a new plan, it's even more important to see whether your doctors are included -- if you're moving to a new plan because it's cheaper, but you have to pay out-of-network prices, the new plan could end up being more costly than your original one.

To check whether your doctors are covered, you'll usually need to research the specific plan. Most insurance companies allow you to look up healthcare providers on their website to see whether they're in-network. But this method isn't always the most reliable, as networks change regularly and websites aren't always up to date.

Another route you can take is to call your doctor's office and ask if your particular doctor is in-network with your particular insurance plan. Be as specific as possible here, because sometimes doctors are in-network with some plans and not others, even under the same insurance company. If you have your doctor's tax ID number, you can also call the insurance provider's general line and ask if your doctor is in-network with the specific plan you're looking at.

Enrolling in a Medicare plan can be a hassle, but it's important to do your research to ensure you get the best deal. The average 65-year-old couple can expect to spend roughly $280,000 during retirement to cover healthcare costs, and choosing the wrong plan can make healthcare more expensive than it has to be.

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