I have two litter boxes for the two cats. One of them might use the second one once a week to pee, maybe twice. For about a year, they used them both equally but since around January, it's just the one. I'm fairly certain, once I take it away, they will start peeing in that place. Or at least complain. They pop in once in a while, dig a bit and then walk away. The digging is just for fun. I cleaned it, disinfected it, replaced parts, I even used parts of the favorite one (it's a whole system). No change. At least the favorite one is in the laundry room, so I'm ok with it all.