I'm laughing at myself because I've never done enough ironing to change them or wear them out. Usually we've broken the board (until this last one I could only afford the cheapest, wobbliest ones.)
For my starched piecing, I took an old pillowcase, cut out the seams and lay it over the board to work on.
But if I had to change, I have some heavy home dec cotton fabric I'd use to recover.