I use them on bad first cleans for upstairs sills, and conny roofs.
I also have a green Synthetic sponge Scourer roll from b&q that's 6mm thick, 140mm wide by 3m long for about £5. I cut sections out and use that, it lasts a lot better than the Gardiners pads but I only use it on glass conny roofs and sills. I use the original Gardiner pads on polycarb.