The 5 most costly errors are:1. Focusing Only on the Premium2. Assuming Your Doctors Are Covered3. Ignoring Prescription Drug Formularies4. Copying a Friend's or Spouse's Plan5. Missing Key Enrollment Deadlines Selecting the wrong Medicare plan can result in large out-of-pocket costs and limited access to care when you need it most. Click to schedule a free consult and avoid these Medicare Mistakes.