If your sofa arm has seen better days, you have probably already discovered that telling a cat not to scratch simply does not work. The good news is that scratching is not bad behaviour to eliminate, it is a natural need to redirect - and once you understand why cats do it, solving it gets a lot easier.
Scratching is not just about claws
Cats scratch to shed the outer layer of their claws, but also to stretch their whole body, mark territory with scent glands in their paws, and simply relieve stress. It is a genuine physical and emotional need, not a habit to be trained away entirely.
Give them something better than the sofa
The trick is not stopping the scratching, it is offering something more appealing than your furniture. A sturdy scratching post or board, positioned somewhere your cat already spends time, is usually all it takes.
Location matters more than you would think
Cats tend to scratch first thing after waking up, so a post near their favourite sleeping spot gets used far more than one tucked away in a spare room. Near a doorway or by the sofa itself, right where the damage has already been happening, often works best of all.
Vertical or horizontal, offer both if you can
Some cats prefer stretching upward against a tall post, others prefer scratching low and flat. If your cat is ignoring a vertical post, do not assume they are just being difficult - try a flat or angled scratcher instead and see if that is more their style.
Texture is a genuine preference
Sisal rope, corrugated cardboard, and carpet all feel different underpaw, and cats can be surprisingly particular. If one type is being ignored entirely, it is worth trying a different material before assuming the whole idea has failed.
Be patient with the transition
If your cat has been scratching the sofa for months, it will take a little time and consistent redirection to shift the habit elsewhere. A bit of catnip rubbed onto a new post can help speed things along in the early days.