We used to have two boxes (2 cats), but they both grew up together so they seemed perfectly content to use the same box.
My husband, bless his heart, takes care of the litter box. I wouldn't care to, but the dust aggravates my asthma like smoke would. Even trying to keep the dust down or buying a different type of litter doesn't seem to matter. It's like when the nose smells liter, the lungs close up.. Ack.
He takes care of it every morning and there's only been a couple of accidents since them (mostly because a human was in the bathroom where we keep the box and one of the kitties really had to go!)
Love their precious hearts