Campos is a strong proponent of employee accountability. He’s taken the same approach to managing mobile usage, which he says is one of the top three internal expenses his department oversees. Each new hire that comes through the door is given the same choice—iPhone or Android device. Facebook picks up the monthly voice and data tab, but employees receive a copy of their bill each month so they can personally keep track of their usage patterns and corresponding cost to the company (they can even see how they rank relative to their department’s averages). To track these costs and provide employees with the necessary data, Campos uses a service from a company called Apptio. Like the vending machines, that’s helped Facebook cut costs incurred by employees. Of course, it’s also led to several managers calling out workers with expensive roaming habits, though Campos says it’s all been done in the spirit of positivity.