If you are on Medicare, watch your mailbox closely. Social Security is going to send you a new Medicare card. The reason they are doing this is to correct an error many decades in the making.
When Medicare began, the program used people's Social Security numbers as their Medicare ID numbers. This probably seemed like a rational idea at the time. Flash forward to the Internet age
when identity theft is rampant. Suddenly, reusing Social Security numbers as Medicare ID's does not seem very smart.
While Social Security claims this transition to new Medicare ID's will go smoothly, I'm not so sure. I suspect there will be a great deal of confusion as this change over takes hold. Consider that every medical facility that accepts Medicare (basically all of them) are going to have to update their records with new ID's. I also fear that many Medicare recipients won't get their new cards or even hear about the change.
Social Security will start sending out the new Medicare cards next April. There is plenty of time to get the details right and ensure a clean transition. If you get Medicare, you can do your part by looking for the replacement card and supplying your doctors with your new ID.