You first become eligible for Medicare when you reach age 65. Your enrollment window will begin three months before your 65th birthday, last throughout your birthday month, and extend for three months afterward. During this time, you will enroll in Medicare for the first time, or be automatically enrolled if you’ve already claimed your Social Security benefits.

You might think enrollment consists of simply choosing between Original Medicare and Medicare Advantage plans, but that’s not the only decision you will face. In fact, one more decision is perhaps even more important at this time, because it’s the optimal time to enroll in a Medicare Supplement (Medigap) plan.

A Medicare Supplement plan works alongside Original Medicare (Parts A and B) to fill “gaps” in your coverage. Since Original Medicare doesn’t provide 100 percent coverage, many people opt for a Supplement plan to cover expenses such as their copayments, deductibles, and coinsurance. These plans can also provide for the cost of medical care when you travel outside of the United States, making these plans an important consideration for those who plan to travel frequently in retirement.

But here’s the catch: You’re only guaranteed eligibility for a Medicare Supplement plan during your original six-month enrollment window. During that time, you can enroll in a policy without a required health screening to pass underwriting.

Yes, you can always attempt to enroll in a Medicare Supplement plan later, but you will be required to pass underwriting in order to access a plan. Some people will pass, and some won’t. Therefore, if you enroll in Original Medicare and think you might want a Supplement plan to go along with it, the best time to consider this option is during your original six-month enrollment window.

Supplement plans are not available to those who enroll in a Medicare Advantage plan, however.

As you can see, Medicare enrollment consists of a number of complex decisions, each influencing the next. As you approach Medicare availability, remember to consult with a qualified Medicare professional who can guide you through these decisions. Then, we can help you each year thereafter, during Medicare’s Annual Election Period each fall.