The short carpet posts never seem to wear out, and I found it is because my cats don't really USE the short posts. I bought a 3' tall carpet post that they LOVE! They have used it so much, they've 'combed' the carpet at the top 1/3rd and it doesn't work well for scratching anymore.
SO...I took a pair of Hubby's ruined work-jeans and cut/sewed a leg to fit snugly over the carpet post and now they love scratching on that!
I also have a 3' tall sisal post they love. Curly will leap across the room onto it and rock it almost to the floor. After seeing them with the sisal, I have mentally marked that as one of their faves, along with cardboard.