Scratching is not a bad habit. Cats scratch to maintain their claws, stretch their bodies and leave visual and scent signals. If a sofa arm becomes the favourite target, the useful question is why that location works so well.
Location is important
Scratchers hidden in an unused corner may lose to furniture placed directly in a cat’s normal route. Try positioning an appropriate scratching surface close to an existing scratch location, sleeping area or entry point into a favourite room.
Offer the right orientation
Some cats prefer vertical scratching posts that let them stretch fully upward. Others strongly prefer horizontal cardboard surfaces. Providing both can reveal a clear preference.
Stability matters
A scratching surface that tips or slides can be less appealing. Make sure vertical posts are stable and horizontal scratchers do not move excessively during use.
Make the approved spot rewarding
Play near the scratcher, place it where your cat naturally spends time and praise calm use. Avoid forcing their paws onto the surface, which can make the object feel negative.
Protect furniture while habits change
Temporary furniture covers or rearranging access can reduce damage while you establish a better scratching location. Punishment is unlikely to teach the alternative behaviour you actually want.
Sudden excessive scratching combined with anxiety, skin problems or other significant behaviour changes can warrant professional advice from a veterinarian or qualified feline behaviour professional.