The transition from full time to fully retired is huge and shouldn't be underestimated. I went from 41.5 years full time to ten days a month part time in April 2013 and coming to terms with that has been a challenge both at work and at home.
At work there was an immediate change in that from being a 'key player' with a team, I was sidelined and pretty much kept in the dark, not deliberately. I think it's called unconscious bias, although in some cases it was conscious.
After three and a half years of this I've found ways to deal with it, and I still enjoy turning up.
At home I'm lucky that I have plenty to do, a lot of which is car related and always has been. But I also do (most of) the gardening and the decorating and general maintenance. But having said that, it's a huge change being at home so much. and I find it difficult getting out of bed.
Some friends are about to fully retire. One is a workaholic who lives and breathes work and I do worry about how they will cope with the seismic change when they have no consuming hobbies outside work. One of the others hates work, can't wait to leave but has no big interests so I think he will struggle.
We try to walk every day I'm at home, at least three miles. When I'm at work I walk closer to five miles. On holiday we do up to sixteen miles each day with a plan to increase that to twenty miles, although it does depend on terrain.
We aim to do as much of the SW coast path as we can, although we often redo our favourite sections, and we will explore further into Scotland & Wales. This dovetails nicely into Morgan road trips, so for now the jigsaw is pretty good. Public Transport has been my Gym for the last twenty years!!!