I know this guy, did judo for at least 20 years. Stopped doing that, but kept doing the bodyweight training every other day. Push ups etc.

He's now 70. I hope I can be as fit and strong as he is by that age. He still does his exercises every other day, and he still works in the garden etc.

So, what I do is even if I don't go to the gym anymore, I try to do bodyweight stuff every other day or so. Push ups, belly exercises, squats, pull ups on something. Yes, the gym is more intense, but if I can keep this up for the rest of my life the gains will be there.

I also try to be careful about what I eat, and I'm failing hard at that. I do walk a lot though, I have an active job and also a dog.