If you're wondering why I would buy my cats a chair, this one is really a corrugated cardboard scratcher from Imperial Cat. Cats love corrugated cardboard because it feels very much like the bark on a tree.
Boccelli is a horizontal scratcher. He loves to crouch, dig in and tear whatever he's scratching. Belle is a horizontal scratcher and likes to stretch full length. So Boccelli will like the ottoman, and Belle will love the back of the chair. When they're not scratching, they'll cuddle together on the seat.
Scratching is natural for cats, and they scratch even if they have no claws. Cats scratch to stretch the muscles in their backs and to mark their territory visually and with the scent in their paws. Of course, grooming their claws is another reason for this very important behavior.
Your cats don't need their very own easy chair and ottoman to be happy scratchers. But they do need the right kind of scratcher in the right location. And every cat is different. So if you have several cats, you might need several kinds of scratchers. Katie loves one of our tall scratching posts that's worn down to the bare wood. Sizzle and Muffitt like double wide corrugated cardboard scratching pads. They scratch them, and then they nap on them. Here are more scratching surfaces cats love.
But the location of your scratching posts and pads is just as important as the material you and your cats choose. If you hide them away in a dark corner, they'll be ignored. Remember, one of the reasons cats scratch is to mark their territory. If you put scratching posts and pads at the entrances to rooms where you spend a lot of time, the cats will use them! Other good locations are against furniture they're already scratching (they have a preference for that location) and near where they sleep. There's nothing cats love more than a long, luxurious stretch after a nap.
Just one more suggestion: Be willing to invest in really good, high quality scratching posts that are tall enough for your cat to get a good stretch and stable enough that she won't think the post is going to topple over on her every time she uses it. A post that's too small or isn't well made is hardly worth the money because it will likely be ignored, just like that scratcher in the dark corner. Good scratching posts and pads can seem pricey, but they're a lot less expensive than a new couch!