Open enrollment for Medicare begins today, and beneficiaries will see Advantage plan premiums rise by about 5%, the number of plan choices increase by about 7%, the average basic premiums for drug plans go up by about 33 cents and premiums for seven out of the 10 most popular drug plans rise by double-digit percentages. Consumer advocates said beneficiaries should pay attention to premiums, copays, deductibles, plan formularies and prior approval restrictions when choosing their plans during open enrollment, which ends Dec. 7.