Fitting it so your cat actually uses it
Three things rescue more installations than anything else — and two of them cost nothing.
Fit it at your cat's height, not yours
Cats groom their cheeks against something at head height while standing, not while stretching up. Two or three centimetres too high is the most common reason a groomer is ignored.
Make it solid
A groomer that shifts when a cat leans in teaches the cat it is not safe. Screw fitting is the safest on plaster and wood; if you use the adhesive pad, wipe the surface dry and dust-free first.
Do not introduce it
Carrying your cat over and rubbing its face against the brush creates avoidance. Fit it, walk away, let them find it. Most do within a day.