That's good to know that they get a lot more active as they age. I've observed that change in his behavior and I guess I wanted him to be able to have a combination of being able to run around on flat ground in addition to a wheel to give him some variety. He used to love doing sprints back forth on the ground in his old play area in addition to playing in the big PVC tube maze I made for him. I haven't been able to setup the tube maze in our new place since we simply don't have the room for it now, so the wheel has become his go-to exercise tool.
I was taking the wheel out of his cage for two reasons: 1) the noise the wheel makes that keeps me awake since I'm a light sleeper and 2) to keep the cage clean since I'm able to clean the wheel during his play time. When his wheel gets dirty/poopy, he'll stop running on it and actually wait for me to come and take it out of his cage to clean before he'll get back on it. He seems to like having clean feet as much as I like having his cage clean which is also great, it just means I have to be awake while he's playing. I may have to start leaving his wheel in his cage though and clean it the first few hours, wear ear plugs at night and clean the wheel again in the morning.
I just hope he warms back up to me.