Medicare's open enrollment period is in full swing, and now's the time for seniors to review their plan choices and decide whether to keep their existing coverage or switch plans for 2021. In fact, enrollees are often encouraged to think about switching plans. But before you go that route, ask yourself these important questions.

1. Did my coverage suffice this past year?

Before you contemplate switching to a new Part D or Medicare Advantage plan, you'll need to think about how your coverage held up this past year. Were the services you needed generally covered? What about your medications?

Diamond-shaped road sign in field saying open enrollment ahead

Image source: Getty Images.

If you were on original Medicare this past year and found that you spent a lot of money on dental and vision services, which aren't covered by original Medicare, then that could be a good reason to switch over to Medicare Advantage, which usually picks up the tab for those services. Similarly, if your out-of-pocket prescription costs were exorbitant, then it definitely pays to look at different Part D plans.

But if you were generally happy with your coverage and found that it didn't eat up too much of your retirement income, then you may not need to switch at all -- provided your plan is largely staying the same, which we'll discuss next.

2. Has my plan changed in a negative way?

All Medicare Advantage and Part D plans have the potential to change from year to year. The good news, however, is that they can't change without warning.

As an enrollee, you'll be entitled to a notice of change that's delivered in time for fall open enrollment. If you're happy with your existing coverage but it's changing in a manner that's unfavorable -- say a medication you take is being bumped into a higher tier, making it more expensive -- then it pays to look at getting a new drug plan. But if your plan isn't changing for the worse and you're satisfied with it, then it could pay to keep it.

3. Has my health changed?

If your health needs are changing -- say you've recently been diagnosed with a chronic condition or you're about to start a new medication -- then you'll really need to research different plan choices to see where you'll get the best coverage given your new circumstances. But if your health has stayed the same, your prescriptions are staying the same, and your plan is staying the same, then there may not be any reason to make a move.

Don't assume you need to switch plans

Let's be clear: It's always a good idea to compare your plan choices during open enrollment and see what your options look like. But there's also no need to go into open enrollment assuming you should switch plans. It may very well be the case that you're already on a plan that's suiting your needs, and while it's important to do your research, there's also nothing wrong with keeping a plan that seems to be working for you.