Ask the Experts about Medicare Advantage and Medicare Part D enrollment and changes. The open enrollment period for 2011 coverage started on Monday and continues through Dec. 31, 2010. Lisa Walker of Bay Aging and Margaret Mondul, owner of a household documents organizing company and an expert on Medicare Part D, can answer your questions or direct you to the resources you need to help you make this important decision. They can also answer how the health-care reform bill will affect coverage next year.