In the white collar professions, on balance doctors and lawyers appear to work longer than many others.
Not sure why.
Having worked with a lot of these folks, I'll venture some guesses:
1. Their identity is closely linked to the image of being a doctor or lawyer, and they find it hard to give up the intangible benefits that come with that (feeling valued, prestige, people looking up to them, being treated with respect, etc). Also, they've worked so long and hard to be a doctor or lawyer, they find it hard to let that go. It is a very big part of who they are.
2. They find their jobs intellectually stimulating/challenging and socially fulfilling, and they don't want to give that up.
3. They've often been so busy with their jobs and families that they have had very little time to discover other interests or hobbies. They wonder, "What would I do with all that free time?"
4. High living expenses. If you're a doctor, you'll feel peer pressure to live a certain lifestyle that matches your colleagues. Keeping up the Dr. Joneses, so to speak -- big house, nice cars, lavish vacations, private schools, etc. Plus you've got the trophy wives (or trophy husbands, I guess?) driving up expenses.
5. Alimony and child support payments to two or maybe three ex-wives. I remember a brief Saturday Night bit from decades ago. It was an ad parody, with all these dolls or action figures, each representing a certain profession. There was one figure that was a surgeon. The line I remember was, "Third wife optional." That's been true in my experience. I've known a lot of docs doctors who made really poor choices in romantic partners (e.g., very attractive borderlines), then got burned/soaked during a divorce. Those divorce costs and child custody payments can add up.
6. They feel like they're useful and making an important contribution to society, and they don't want to stop.
7. I'd also add that some doctors and lawyers don't make nearly as much as some people imagine. Yeah, there are some with half a million salaries, but I've also known primary care docs who are barely squeaking out a living. So they may not be in a position to retire.