AppleCare representatives are in charge of providing data to Apple’s senior executives and engineers about defective devices and publish a weekly report highlighting the three most common problems reported by customers, the former employees say. They sit in on early design meetings and can marshal engineers from other product teams to fix problems. As with the early iPhone bugs, most of the problems they’ve discovered over the years relate to components not being connected properly, Wilhelm says—an unfastened cable or too little glue or solder. “If you can find a problem in the first week or less,” he says, “that can ultimately save millions of dollars.”