Last week, a regular customer came in for an oil change and was sighing in the waiting room. "I was planning to switch from Advantage to Medigap this year, but I got denied by the insurance company."

When I asked why, they mentioned they had been hospitalized for heart issues last year. That one line caused their application to be returned.

I was skeptical at first. I thought anyone could change plans during Medicare's open enrollment period.

So I did some research. To sum it up, while switching from Advantage back to Original Medicare is straightforward, enrolling in Medigap is a completely different story.

This year's Medicare open enrollment runs from October 15 to December 7. During this period, you can cancel your Medicare Advantage plan and return to Original Medicare without any issues.

During the Advantage open enrollment from January 1 to March 31, you can also switch back to Original Medicare once.

The problem is that Original Medicare does not have a cap on out-of-pocket expenses. Therefore, most people want to add Medigap, or Medicare Supplement, to their coverage.

However, Medigap insurers are not bound by this open enrollment period. Unless it's a legally mandated guaranteed issue period, they can conduct health underwriting.

The items assessed during health underwriting are quite specific. According to KFF data, they ask about recent hospitalizations, medications being taken, and any recommended tests or surgeries that have not yet been completed.

If you have conditions like cancer, congestive heart failure, complications from diabetes, or Alzheimer's, you could be denied coverage altogether. Even if accepted, your premiums may be higher.

According to an analysis by KFF released in October 2024, 90% of Advantage enrollees over 65, which amounts to 22.4 million people, live in states without these protective measures. This means that once the trial period is over, avoiding health underwriting becomes difficult.

I was honestly a bit shocked by this number. It means that nine out of ten enrollees over 65 are facing the same trap.

Only four states—Connecticut, Massachusetts, Maine, and New York—mandate guaranteed issue for everyone year-round. South Carolina is not one of them.

Currently, the birthday rule, which exists in some states, is also absent in South Carolina. The state only follows the federal minimum standards, leaving fewer options.

That said, there are still some paths available. There is a trial right established by federal law.

First, if you enrolled in Advantage when you first became eligible for Medicare at age 65, you can switch back to Medigap without health underwriting within the first year of enrollment. At that time, you can choose any Medigap plan sold in your state.

Second, if you originally had Medigap but canceled it to join Advantage, you can return to your previous insurer's plan within 12 months if they still offer it. If that plan is no longer available, you can choose from Plans A, B, K, or L. If you became eligible for Medicare before 2020, Plans C and F are also options.

Third, if your enrolled Advantage plan withdraws from your area or terminates its Medicare contract, you gain guaranteed issue rights. This is why it's crucial to carefully review the plan change notices that come every fall.

One number you absolutely cannot overlook is 63 days. You must apply for Medigap within 63 days of the end of your Advantage coverage to maintain this right.

The customer had been using Advantage for over five years, so their trial right had already passed. Ultimately, they decided to keep their current plan this year.

One thing I've learned from my long experience in car sales is that those who check for ways to backtrack before signing a contract tend to avoid losses.

The same goes for Medicare. Before canceling Advantage, you should submit your Medigap application and secure your approval letter before proceeding with the cancellation.

If you reverse the order, you might find that your Advantage plan is already canceled while your Medigap application is denied, leaving you with only Original Medicare. This is the scariest scenario.

Don't forget about prescription drugs either. The coverage for medications included in Advantage will disappear, so you'll need to enroll in a separate Part D plan.

If you're unsure where to start, consider using the free counseling service I-CARE, operated by the state's Department on Aging. It's South Carolina's SHIP program and is not affiliated with insurance sales.

Since the results can vary significantly based on your medical history and medication use, I recommend consulting with a counselor or a trusted insurance expert before applying.

Some argue that all states should mandate guaranteed issue enrollment year-round like New York. However, estimates from Minnesota suggest that implementing such a system could increase average premiums by 6% in the first year.

I believe that rather than making everything mandatory, it's more important to properly inform people about their first choice at age 65 and the first year trial period. Ultimately, the costs will be shared by those who enroll healthily in advance.

If you're currently using Advantage and considering switching to Medigap this fall, make sure to get your health underwriting results before December 7. The cancellation button comes after that.