First thing:
My father in law retired last year. He is the highly intelligent, but with a significant manual how to deal with him. Since his social world has changed - no work environment anymore - the family is the only social environment he is in and given the complexity to deal with him it is quite a challenge for the children. We truly love and respect him though which makes it more difficult.
Everybody is looking forward when he starts contracting part time in a few weeks time helping a mid size transport company getting the logistics right. He is the right person for the job and hopefully this gives some pride back and reliefs us from the same stories over and over again.
Ergo, make sure you have a social network which is appropriate for the needs of yourself and the ones around you.
Second thing:
Being 40 and a bit, I have received great help from a pre-retirement colleague in organising my work in designing complex software in the last few years. I still wonder why I never had someone like him earlier in my career when I had to figure it out myself all the time. Simple methods, like always have a second pair of eyes check the software, share ideas, or encouragement to stick to the process even when a shortcut seems appropriate.
Therefore a big thanks to those consulting and coaching younger fellows.