Jerry and Gizzy have the run of the house when either me or my hubby are in , but when we are out we shut them in the spare room as Beavis needs a bit of space , and also if the kittens are about the catflaps have to be locked and windows shut and of course then Beavis cant get outside if he wants to - if we are in we let him in and out!
They have lots of toys , a litter tray , and beds in their room , and its a reasonable size , but I do feel guilty about leaving them in there.