Do I Need Insurance In Addition To Medicare? 
No you do not need a medicare supplement or medicare advantage plan . That said , your life will be much easier to deal with medically if you do have the above mentioned plans . As Bob mentioned an unlimited 20 % hole in your coverage has the potential to put you on the street . Also , many medical offices are not accepting patients with just medicare anymore as they are being asked to take a financial hit with each medicare patient as medicare does not pay full cost of care for services received . Medicare is a deep discounted program and for many practices the idea of not getting some relief from payments from the other insurance plans just does n't work for them . 