Posted by MedEd at MHI
A: The best time to buy a Medicare Supplement plan is when you are not required to go through the medical underwriting process (answer questions about your health). You don’t have to answer any medical questions if you purchase your supplement plan within six months of your Part B effective date.
There are a few other special circumstances covered under “guaranteed issue rights” that will also excuse you from the underwriting process (see Medicare’s Choosing a Medigap Policy publication).
Members Health Insurance will not ask any medical questions if you apply for their supplement within 63 days of losing any type of employer coverage (current employment, COBRA or retiree coverage). This is a company-specific policy; all companies do not have this policy.