Note:
It will take two to three months for your premium deduction to begin after your coverage starts. When you first join a Medicare drug plan, your premiums for your first two or three months of coverage will be combined. For example, if you enroll in or switch Medicare drug plans in December for coverage that begins in January, your first premium payment will probably be due in February. It will include your premium for January and February.
(Primary Source: Centers for Medicare and Medicaid Services - Medicare and You Handbook. This content may have been enhanced by Q1Group LLC to include further examples, explanations, and links.)