We mounted plywood under every bed we own.
I measured and cut out black hard foam core to fit flush and around the legs and nailed it to the bottom of every upholstered
chair in the house. Kitty has found other things to do that are not as destructive.
Our cat has made a project of tearing up the black fabric liners under the beds. He even climbed up inside the box springs.
It is a lot of trouble, but we went to Lowes and had lightweight boards cut to the size of the box springs and sandwiched them between the box springs and the bed frame...
