Part D do’s and don’ts
For most people, signing up for Part D at 65 is the best strategy. But be prompt. There’s a penalty—1 percent extra on your premium for every month you could have signed up, but didn’t—for enrolling more than three months after your 65th birthday month. So if you are a year late enrolling, your premium will be 12 percent higher than it would have been otherwise.
There are exceptions to signing up right at 65, though. See Medicare Part D for more information.