As i work in the building trade so my hands & fingers get ruffed up quite often. Because of this reason I think Touch ID has a hard time trying to read my prints due to the cuts, ruffed up skin, scratches ect that can change on a daily basis. I know 100% there is nothing wrong with the touch ID sensor on my 5S, as my girlfriend has no problem at all with it when she uses it, because she got nice soft hands. It's got to the point now were i just turn it off and use the password instead as this is less hassle to me. Anybody else that does manual work finding the touch ID sensor has the same problem when reading your prints.