Two kitties, one huge box in this house.
The only problem we've ever had was Gibbons spraying in one particular room of the house, so we closed that room off so he has no access, problem solved thus far.
I scoop the box at least once a day. My kids love to help with the 'animal upkeep' as we call it here, so they actually help me with scooping duty (and a supervised hand washing afterwards
As long as we keep the box in a certain spot in the back hall, kitties are happy. Moving the box led to peeing on the laundry, so lesson learned by me. My boys are good teachers