I use these pads in my home office where floor is covered with 7/8" thick commercial solid foam padding and thick plush carpet. The chair glides easily over the surface and protects the carpeted area.
Like others have mentioned within days the plastic molds to the chair wheels creating divots that make it difficult to move the chair out of. However after a couple weeks these became less noticeable. I don't know if I've just gotten used to it or if the plastic just started getting more pliable with use. It's still better than not having one.