@helli it's the inconvenience. Having to contact them is not easy on the phone - I will try the on line form next time. I have tried plasters. Only one sensor fell off, the rest have all stopped scanning. You're right about the warm up period and the time to actually get a new one on etc and when you call them the first thing they ask after ID checks is whether you were unconscious and if you had any first aid administered by anyone other than yourself. So, they are aware of the issues. I've read elsewhere on this forum that the sensors were great until about six months ago. Maybe it's a faulty batch or a change in the manufacturing process.