Cardboard scratchers are mainly for horizontal scratching. The surface sheds and needs regular replacement, but it is cheap, can lie flat or slope, and works well for the trial stage.

Sisal posts are mainly for vertical scratching. The fibre is durable and lasts longer, but it takes more floor space and some cats dislike the rough feel.

Scratching direction varies by individual: a cat that claws the side of a sofa may accept a flat cardboard pad, while one that stretches against a post usually prefers sisal.

A safe approach is to offer both and restock based on observed use. Placement matters more than material: put scratchers on routes the cat passes after waking.