I’ve just finished an iPhone 4S screen replacement. The phone turned up half disassembled with the screws, brackets and retaining clips all mixed up. The first job was to measure all the screws to the nearest 0.1mm. Not surprisingly there were 3 screws missing and the rubber surround for the home button. From there onwards it was a straight forward screen repair. The customer was charged £75 and she had her iPhone back in as new condition.