Your 65th birthday is coming up. Soon, you think, the government will send you a packet explaining how to enroll in Medicare — its vast health program for 46 million seniors.

Don’t hold your breath.

Astonishingly, no coordinated effort to reach out to soon-to-be-65-year-olds exists. You have to figure out what to do — and when to do it — on your own, along with 10,000 Americans reaching the age of Medicare eligibility every day.

Give yourself plenty of time.