Mix rather than swap: a quarter new litter for several days, then half, then most, over two to three weeks — cats object to sudden substrate changes far more than to the substrate itself.
A gradual change costs nothing and prevents the most common cause of a cat going elsewhere.
The schedule
Quarter new for three or four days. Half for another three or four. Then mostly new, then all. If the cat hesitates at any stage, go back one step and hold there for a week.
Do it before the machine arrives
If you are switching to an automatic box that needs a different litter, make the litter change first, in the old tray. Two changes at once produce a refusal you cannot diagnose.
Signs it is going wrong
Digging outside the box, perching on the edge, shorter visits, or going elsewhere entirely. All of them mean back up a step.
Buy small first
A 4.5 kg (9.9 lb) bag is the right size for a trial. The 10.8 kg (23.8 lb) bags are for after the cat has agreed.
Last reviewed 2026-08-17