I keep 1 rat per small plastic container, with food, water, and a hide. Then I keep the container in a dark part of the room and never really bother to check on them or do anything with them unless I think the substrate needs to be changed (the water will last them a week, and the food is usually a heck of a lot for them. So there you go, I don't bother with large spaces or exercise wheels, and I don't keep them for more than a week. They, like the snakes, want tight dark spaces, food and water. Although, unlike the snakes, they want companionship. So I suppose keeping more than one together in a larger container would be better so they could have someone to spend time with.

They don't really "need" exercise wheels or climbing devices. They're happy as long as they have the basics for life; food, water, comfort. If you don't ant to keep more than one at a time then you can play with them yourself and they are EXTREMELY happy about it, provided you know how to show love to a small animal. Within 5 minutes I have them licking and nuzzling me... this is why I stopped feeding live rats. I like them, they like me, I can't keep them as pets since their presence puts my snakes in feed mode (which is uncomfortable over long periods of time). Either I get them the day I intend to feed them to the snakes, or I get frozen.