@dmertz wrote:
I believe that the lookback is 6 months or to the month that you reached age 65, whichever is later.
https://www.medicare.gov/basics/get-started-with-medicare/sign-up/when-does-medicare-coverage-start
Right. This taxpayer is planning to enroll at 67 or 68. The exact rule, as I understand it, is that if you enroll during the standard enrollment period (which is from 3 months before to 3 months after the 65th birthday, the enrollment is effective on the first day of the month in which you turn 65. If your birthday is the first, your enrollment is effective the first day of the previous month. If you enroll after the standard enrollment period, the lookback period is 6 months, but never earlier than first day of the month in which you turn 65.
