If you enroll early in the month, there is a better chance you will have your membership materials when your coverage starts.
If you don't have any of the above, and your pharmacist can't get your drug plan information any other way, you may have to pay out-of-pocket for your prescriptions. If you do, save the receipts and contact your plan to get reimbursed.
Enroll early in the month. This gives the Medicare drug plan time to mail you important information like your membership card, acknowledgment letter, and welcome package before your coverage becomes effective. This way, even if you go to the pharmacy on your first day of coverage, you can get your prescriptions filled without delay.
(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.)