Our larger cages have wheels. Some have chin spins, others have flying saucers. If there's room for a house, there's probably a house in the cage. If there's only room for a hammock, then there's a hammock in the cage.
One thing that's in every cage is a chew toy... at least one, usually multiple, bordering on overkill. I'm personally always amazed when someone gets a large cage like a ferret nation or critter nation cage (which, for those that don't know, are 3' wide, 2' deep, and about 5' high) and put ONE chew toy in the entire cage. I guess, to me, it's boring. But more importantly, it's not stimulating.
Part of the fun in decorating the large cages, in my opinion, is getting to put in different play things. Different textures. Take this cage for example:
This was a pic from years ago, but most of those items are still in there, and it looks pretty much the same, albeit a bit more chewed now. There's the wood from the shelves, which is solid, and one texture. There's the dowels which make up the bridge, which move when the chin runs on it. There's the double hammock which is soft and fluffy. There's a wood perch in the back right corner, which is another texture. There's the fleece tube which surrounds the chins and makes them feel safe. There's the hollowed-out-log in the top left, which is yet another texture and another hiding spot (for smaller chins). Now, there's also a flying saucer in the spot where the house is, so the metal from that is yet another texture. There's the fleece liner and fleece bed for the chins, also soft, but firmer soft, as they are against the metal pan. For chew toys... there's plain wood, there's loofah, I even spot some antler on some of those chew toys. Variety.
The reason this is important is because it's a form of enrichment. Especially for some chins that we get in, that have been kept in a glass aquarium their entire lives, it's neat to see them check out a hammock. They're surprised when it moves, and aren't sure what to make of it. Same with that bridge... it's solid... but it moves... they're not sure what to do... but they figure it out.
For practical purposes, these different textures also help develop callouses on their feet, which are necessary for life. You don't want the entire cage too soft, or these won't develop.
Same goes for the chew toys, we don't want them to be bored. So, instead of them being all wood, we add in ones with pumice, or sometimes even loofah or other chin-safe munchies that we may have. Since we have our wood shop, pine wood is often the go-to toy part for us, but we'll add on other fun stuff from time to time, as it's useful for the chins to have different textures to munch on. Some like the softer wood, some prefer the harder. Some won't touch pumice, some love the loofah. Others just like the plain wood. We like to provide a variety, so they can pick and choose, and not be stuck to one toy, which they may or may not like.
If you look back at the picture, you can actually spot 6 chew toys (or at least I can, but I know where they are). There's also quite a few, so the chin doesn't have to be in the same area of the cage all the time to chew. What if you put the chew toy in the front corner, but the chin doesn't like that corner? Some chins are more shy than others, so we scatter them around the cage, for variety.
Of course, they do chew on the shelves, bridges, and what not... that's why those items are wood as well... but the chew toys can add more variety.