When does Medicare open enrollment take place? Here's what to know when picking your plan.

You may have noticed the increase in TV commercials and flyers in the mail reminding you it's that time of year again.

Nope, not the midterm election.

It's open enrollment period for Medicare plans, running Saturday to Dec. 7.

It's when beneficiaries can switch to a different plan, add prescription benefits or make other changes to their Medicare plans.

With hundreds of options to choose from, here's a rundown of some things to know about Medicare whether you're signing up for the first time or looking to make a change during open enrollment:

What to know about Medicare brokers

Medicare didn't used to be so complicated.

"The people who talk about Medicare for all are probably not envisioning the system that we have today where private plans have a huge role in the current Medicare program," said Tricia Neuman, executive director of Kaiser Family Foundation's Program on Medicare Policy.

Before the rollout of Part D prescription plans in 2006, most retired Americans were enrolled in traditional Medicare, with the option to add on some supplemental plans.

Since then the popularity of Medicare Advantage plans run by private insurance companies has grown significantly.

Neuman said about half of all people on Medicare are on Medicare Advantage plans.

Consequently, there's an entire industry of Medicare agents and brokers who help people navigate their options, but who also are making money off selling these private insurance plans.

It's important to know how they operate.

The consumer doesn't pay for any of these services. But because of affiliations with certain insurance companies, people might not be getting presented with all their options, said Benjamin Link, a pharmacist and vice president of pharmacy for Ohio-based drug analytics firm 3 Axis Advisors.

"You're not really shopping the whole market, you are shopping what they are kind of predetermined to say is good," Link said.

Lisa Miller of Wilmette, Illinois, said that was the experience her mom and others had when signing up for Medicare in the past.

"You call one place, and they're associated with just that type of a group or something, and they're not checking all the best possibilities for you," she said. "At the time my mom did it, she didn't know what to do or where to go."

Miller said that's how her mom ended up on a plan that charged thousands more for her prescriptions.

Link said consumers just need to be aware of these affiliations so they can make an informed decision.

For example, AARP, a name associated with discounts and information for seniors, now has a partnership with the insurance provider UnitedHealthcare to sell Medicare plans.

Jane Sung, a senior strategic policy adviser at the AARP Public Policy Institute, said they've licensed the name AARP but the arm that sells insurance is completely separate from the main organization which offers educational information about Medicare through its publications.

Can you enroll in Medicare anytime?

Timing is the first step when initially enrolling in Medicare.

There is a seven-month window around your 65th birthday called the Initial Enrollment Period when you can sign up for Medicare for the first time.

"That is not obvious to a lot of people," said Cobi Blumenfeld-Gantz, CEO of the Medicare startup Chapter. "Most people think that, 'Oh, if I'm 65, but I'm still working, I don't need to sign up for Medicare.'"

In some cases that's correct.

But if you defer signing up for Medicare prescription drug benefits and don't have what's called creditable coverage through your employer, you will be penalized.

Creditable coverage must cover as much as or more than Medicare Part A and Part B, according to the Centers for Medicare & Medicaid Services.

Blumenfeld-Gantz said some small businesses may fall short.

"So if you work in a small business that's 15 people and they give you health insurance and you're 66, you're actually accruing penalties from the government," he said.

MEDICARE: Enrollment123 is streamlining a complex program and making it user-friendly

The penalties exist to encourage people to sign up as soon as they are eligible for Medicare, ensuring cost savings for the government by having the maximum number of people enrolled.

According to Centers for Medicare & Medicaid Services, late enrollment penalties go up the longer you wait to sign up, are added to your monthly premium and are charged for as long as you have that coverage.

For most people that becomes a lifetime penalty. For example, your premium goes up 10% for each year you are late in signing up for Part B coverage and stays at that higher rate forever.

The Centers for Medicare & Medicaid Services has a tool to determine when you should sign up at Medicare.gov.

After the initial enrollment period, there are two times a year you can make changes: the open enrollment period that begins on Saturday, and the Medicare Advantage open enrollment period from Jan. 1 to March 31. The second only applies to those who are already on an Advantage plan.

There are some circumstances, including moving to a new state, in which you may be able to change plans outside of those windows.

What to look for in choosing a plan

When you turn 65 and qualify for Medicare coverage, you have a number of plan options based on where you live.

For example, a senior living in Cuyahoga County, Ohio, has more than 80 options just for Medicare Advantage plans, according to the Medicare.gov plan finder.

By using the plan finder tool, or through a broker, you can input your prescriptions and your preferred doctors and hospitals to find all the plan options available in your zip code.

For some people finding the lowest price will be the most important factor, for others, it might be keeping their specialist, Sung said.

"If you have a strong preference about seeing a particular doctor or a particular health care provider and that's important to you, you want to check it and see," she said. "Similarly and important to a lot of people, you want to take a look at the plan formularies if there's a prescription medicine that's very important to you, you want to take a look at whether or not that that drug is covered."

Advantage plans have a lot of perks but less flexibility in which doctors are in-network and which drugs are covered, Neuman from Kaiser Family Foundation said.

The premium isn't the only consideration, she said, because some plans have cost-sharing structures that could end up making a hospital stay much more expensive, for example.

Recheck that you have the right Medicare plan each year

"We encourage people to constantly be checking as your health needs change and as Medicare plans change…formularies change frequently," Blumenfeld-Gantz said.

Your doctor could be in-network one year and then the insurance carrier can renegotiate their contracts and drop that doctor the next year.

But many people don't take advantage of the annual opportunity to switch plans, Neuman said.

"People on Medicare know that the annual enrollment period is a time to compare options. They see a ton of marketing advertising on TV. They get a lot of marketing material in the mail," she said. "But while they understand that this is the time to compare plans, few actually do that."

Likely because they don't feel they have the time or expertise to do the research and compare plans again, she said.

DRUG NEWS: Alzheimer's drug slowed progression of disease in late-stage study, drugmakers say

There are also a few rules to be aware of in terms of preexisting conditions.

When initially enrolling, people can choose a Medigap plan with no doctor's visit required. Medigap offers supplemental coverage to traditional Medicare plans.

But if someone initially chooses a Medicare Advantage plan, they can be rejected or charged more to switch to Medigap, Sung said.

Only four states have protections to prevent this. They are Connecticut, Massachusetts, Maine and New York.

Follow Katie Wedell on Twitter: @KatieWedell and Facebook: facebook.com/ByKatieWedell

This article originally appeared on USA TODAY: Medicare open enrollment period 2022: What to know about plan options