Blimey that's more frequent than me! Though I'm only cleaning around 30 houses a week, trad only. I flip the rubber every 2-3 weeks, but find the flip side only lasts 1-2 weeks. It's always the corners that go first with me, so I'll change it then, or if it lasts 3 weeks then it gets changed that weekend regardless. Nothing like wasting a bit of work time changing the rubber to p*** me off!