Seniors on Medicare know all too well that the costs associated with it can be burdensome. While Medicare Part A, which covers hospital care, is usually free for enrollees, Parts B and D, which cover preventive/outpatient care and prescriptions, respectively, and comprise the remainder of seniors' coverage under original Medicare, charge enrollees a premium. The good news, however, is that there are steps you can take to lower your Medicare premium costs, thereby stretching your retirement income even further.