In my experiences - Stay Active & Stay Engaged, live longer happier and healthier life -, I have seen within my own family, that those that retired lost a lot of the desire to live which quickly created lots of medical issues that they eventually succumbed to. I think a happy medium of semi-retired would improve many lives. Maintaining mental stimulation, social connections, a sense of purpose, and physical activity are all crucial for wellbeing as we age. An abrupt transition from full-time work to full retirement can be very jarring for some people.
For example my grandfather ran a large financial services division (entire northeast corridor) and was offered to retire a few months early to allow his planned/trained replacement to start sooner (they were fearing he might leave for another company if he had to wait those extra 9 months). So my grandfather took it and took the opportunity to golf more (instead of2-5 games a week he was going 2x's a day to fill up hours) and he finished all his honey do and home improvements work, and helped wiht a number of projects that my da and I were behind on. After 6 months he had nothing left to do to get him motivated to get up in the mornings, which suddenly had started finding he lots and lots of ailments begin to appear. So he went back to his old employer and took a job as a pool secretary (now we just call them admin assistants) and all those medical ailments disappeared over night as he worked part time, until the office computer revolution in the late 80's - were he just didn't want to keep up with the technology and retired for a second time. in his mid 70's. Retirement doesn't have to mean isolation or lack of purpose. But it takes intention and planning to maintain an active, engaged and fulfilling lifestyle.
I have observed this pattern in multiple family members that nearly all that had little in "career" activities, saw a decline in medical health rapidly. Worth noting however that those that had a large social networks (bridge clubs/book clubs, etc) interactions replaced much of the work social life aspects all had similarly low medical issues post-retirement.
With these observations, I plan on fully retiring, maybe slow down and enjoy more, longer vacations but totally going work free, appears to be a precursor to negative impact on lie longevity and enjoyment of. semi-retirement can keep people mentally sharp and avoid some of those adverse health effects I've observed.