1. How does your cat scratch?
Stands tall, rakes down
Stretches out low and flat
A bit of both
2. What is it scratching right now?
Sofa or chair
Carpet or rug
Door frame or wall
Next to its bed
3. How long is your cat when fully stretched?
Nose to hip, in cm
Your plan
Rule of thumb, not a vet standard: a vertical post should let your cat stretch its full length without the post wobbling. Every cat is different, so watch what yours prefers.