If you are retired and have Medicare Part B
as well as other insurance, Medicare would be your "primary payer," which means it would pay its full benefit amount for any covered medical service; your other insurance would be the "secondary payer," which would pay the costs that Medicare leaves unpaid (such as the 20 percent coinsurance amount for doctors' and most other bills). Between the two kinds of coverage, you would have almost all of your medical bills paid. But it would cost you a $96.40 per month premium for Medicare Part B coverage, plus a yearly deductible of $135, in addition to whatever you must pay for your retiree BCBS insurance. So, you have to calculate whether the additional coverage you get with Medicare Part B is worth the added premiums.
The way to figure out whether the Medicare Part B premiums would be worth it is to calculate how much in medical bills you regularly pay out of pocket under your current insurance. You can use the previous year as an example, adding up all the premiums, copayments, and coinsurance amounts that your current insurance did not pay for covered services (not including things that neither Medicare nor BCBS would cover at all) and that you had to pay out of pocket. If you regularly had out-of-pocket expenses of over $96.40 per month for services that Medicare Part B would have covered, then Medicare Part B might be worth it (if you're likely to continue having the same level of medical expenses).
You can get free assistance doing these calculations from a counselor at a local office the federally funded, non-profit State Health Insurance Assistance Program (SHIP) or Health Insurance Counseling and Advocacy Program (HICAP). To find the office nearest you, you can look in the business pages of your local telephone directory under State Health Insurance Assistance Program (SHIP) or Health Insurance Counseling and Advocacy Program (HICAP). Or, you can go online and using a search engine enter SHIP or HICAP and the name of your state.