The only personal example I can really think of is my maternal grandparents. Granddad took an early retirement at the age of 55, from the federal gov't in 1971. He did it to take care of Grandmom's favorite aunt, who moved in with them in her old age. She died after about a year, but Granddad never did go back to work. Although, he and his brother-in-law did a lot of "shade tree mechanic" work and made some money on the side, at least until downsizing and more complicated emissions controls made cars more aggravating to work on.
Grandmom was forced into retirement at the end of 1980, when Glenn Dale Hospital shut down. She was 56. However, she started doing work from home, doing transcription work or something like that, for some doctors she knew. And at some point, she went back to work part time/on call for a hospital about 15 miles away. Sometimes she'd work almost 40 hours per week, but she could work as much or as little as she chose.
Granddad ended up dying from lung/lymph node cancer in 1990, at the age of 73. Grandmom kept working until she hit 70, in 1994. Even then, she didn't want to quit, but figured that, at her age, it was time, what you were "supposed" to do.
So, my grandparents never really got to spend a retirement together, in the strictest sense. But, I still remember them taking off on a whim here and there, on various road trips, camping trips, etc. In '78 they took my Mom and me on a 2-week trip that ended out in Yellowstone. And in '82 they took me on a pretty major 8-week trip across the country and back, where we just took out time wandering, basically. And there were a few other trips here and there we went on, mostly to the Shenandoah mountains, once out to see some friends in Indiana, etc. And, they seemed to take a lot of trips, just by themselves. It's funny, but looking back on it now, even though Grandmom didn't retire completely until she was 70, it still seemed like she was "always there". Probably, because she was working while I was at school, or work, myself.
Anyway, they seemed to make the most of it, and enjoyed the time they had, even if they never were, technically, retired together.
As for Grandmom, once she did retire, she hated it. She was used to being busy, and having people around, I think. At the time, I was living with her, and so was my uncle. But, I moved out on my own in late 1994, and the dog died in early 1995, and suddenly she went from a life that had always been full of people and animals, to just my uncle...and he worked a lot so she rarely saw him. She actually got depressed, to the point she had to be hospitalized, in the summer of 1995. And then her vision got bad, and when she turned 75, in 1999, she was unable to renew her driver's license. So in her case, to me it seems like the "pre-retirement" era, the 1970's and 80's, part of the 90's, when she was getting a good balance of work and free time, was actually a happier time for her than her actual retirement.