One thing to keep in mind for those whose kitties will not use their scratching posts....
Cat usually like their scratching "landmarks" to be in places that are sticking out or at a traffic intersection. Like how bears will mark their territory by scratching a tree that is located at an intersection of two trails. Cats do not like their scratching stations to be hidden in a corner or behind things. They like to mark prominent locations, so put the posts there instead.
The best "post" we have for our 3 cats is in the hall that most of the rooms open off of. It has dark wood paneling, and I bought a dark brown carpet runner and attached it right to the wall vertically. It's about 2 feet wide and goes 5 feet up the wall. OMG but kitty loves to leap onto that thing and climb up it like a tree, tearing at it with her claws all the way. Looks more like a squirrel than a cat. Cats also like TALL scratching posts, not those dinky 15" tall ones you get cheap. They like to stretch while they scratch. Some kitties like shag carpeting posts, some like sisal rope-wrapped posts. Our 3 all have their own favorite post- all different.
Many of these problems can be solved by finding the right scratching post and the right spot for it. A little experimentation can yield good results.
And keeping the claws trimmed with a nail clipper definitely helps. I do it when the kitty is dozing and half asleep in my lap at my computer.