When our first grandkid was born, my wife went to work the following day, she informed her manager she was retiring so she cam be a full time grandmother. She did,, she left me for a year to help our daughter-in-law. My wife was 55 at time. She is now 66. I retired from the company at 55, but got pulled away by a friend who jumpstarted a new division in another company. It was a good gig. I finally retired retired at age 59, I am now 68.
Retiring early is well worth it. Staying put and visiting grandkids beats the heck out of working. The 4 lathes, including a brand new PM1440TV, a Bridgeport, and other stuff in the garage, and shooting in competition keep me busy when we are not with the grandkids.
In our retirement we have no desire to travel outside the US. We traveled all of Asia and most of Europe when we were both working while the kids were in college. Son graduated from Duke and daughter from Johns Hopkins.
The best benefit I can see in retirement is the spontaneous lifestyle. In 2013 I asked the wife of she wanted to go for a ride, she asked where, I said pack enough for a week. We pointed the car to the West, a month later we were back. No reservation, no plans, just played it by ear where we ate, and where we stayed.
Yes, no regret retiring early.