Some use shavings, some use liners. It's really up to personal preference. I seem to change up depending on who is in my FN cage at the time. I have a quad in one section at the moment and there's no point in my keeping a liner in their section because I'd have to change it far too often. I just use shavings in their cage, but I go through a lot of shavings just for the one pan. I also have a pair up top that I use liners with. Also, it helps if your chin has been litter trained. Mine on the other hand just pee everywhere.