Published behaviour guidance suggests at least one box per cat plus one, so a cat under conflict still has an alternative instead of queueing.

Once the count is met, distribution matters: in a multi-floor home, put boxes on each floor so one cat cannot block the stairs and cut off another's route.

An automatic box cannot simply be counted as three. Check queueing and identification when several cats use it, and keep a standard box as backup in multi-cat homes.

If elimination problems persist at N+1, the cause may be litter type, cleaning frequency or health. Log the pattern and consult a vet or behaviour professional.