Mobile devices have diffused into work by transitioning from being organizational assets to personal communication tools. This chapter examines the perceptions and practices of diverse types of workers, located around the globe, and reveals the often-hidden complexities surrounding mobile use at work. People can use their mobiles to be productive and connected on the job, but they also face challenges. The shift in control over communication means that organizations have reacted by creating bring-your-own-device-to-work policies, banning their employees from using personal mobiles, and practically forcing workers to provide their own devices and be accessible 24/7. Along the way, workers have had to negotiate with co-workers, managers, clients, friends, strangers, and family concerning how and when they use their mobiles. As they try to build bridges between work and personal life, struggles with self-management and temporal mismatches in the form of reachability can emerge.