Originally Posted by big john

You are required to register on the Medicare site when you turn 65, or a couple months before. You do not get drug coverage for free and if you don't have drug coverage you will pay a monthly fine if you do get it later. You can get a Medicare Advantage plan from an insurance company which covers drugs and co-pays, it's a good deal and there are a lot to choose from.

When I retired I was 65 but my "full retirement" age was 66. I worked part of that year and made $23k. At the time the penalty was they would subtract $1 from my payment for every $2 I made over $17k. This goes away in the year of my "full retirement" age, which was the next year. I didn't work that year anyway.
The other consideration is if you collect SS while working you may have to pay taxes on it. I think this also goes away at some point.