To be able to purchase Medicare Supplemental Insurance policies, you must be a member of Medicare Part A and Medicare Part B. Such a policy only covers one person. Each spouse must buy a separate policy. The best time to purchase (and usually the cheapest) is the six month window that starts one the first days of the month you turn 65 and enroll in Part B. If you don’t sign up during this period, it becomes difficult to do this later, and more expensive.
If you are on Social Security Disability, you can also join Medicare after being disabled for 24 months. This makes you eligible to purchase Medicare Supplemental Insurance as well. You can qualify for Medicare under disability no matter your age once you get those 24 months in.
You can change your Medicare Supplemental Insurance plan yearly during the open enrollment period each year. This runs from November 15-December 31 in 2010. Starting in 2011, these dates changes to October 15 through December 7, 2011.
If you change to a Senior Advantage Plan, you have 12 months to change back to your original supplemental plan, a one time only exception to the enrollment period. If you lose your coverage through a spouse, for example, you have a special eight month window to sign up with Medicare, if you did not do so at 65.
Some states provide additional times to sign up for Medigap polices, but most people wind up paying a lifetime penalty for not signing up at the proper time. This penalty can grow up to 10% of your premiums, which no one on a limited income needs.
Medicare Supplemental Insurance policies are offered on a state by state basis. If usually pays to shop around for these policies. Remember to review all the types of supplemental insurance available to find the one that works best for you. Medigap plans come in Plans A through M, excluding Plans E, H, I and J starting in 2011.