The N+1 rule bends for automation but does not vanish. One machine covers capacity, never location. Here is what five years with three cats taught me.
Do You Need a Second Automatic Litter Box?
The trigger is behavior, not drawer volume. And the second box does not have to be automatic, a plain pan provides a location just as well.
Can One Automatic Litter Box Handle Three Cats?
Vendors say one auto box handles 4-5 cats. Vets say three cats need four boxes. After five years and three cats, here is where the truth actually sits.