Apple CEO Tim Cook once opened up about his personal screen-time habits in an exclusive interview with CBS News. Despite being the architect of Apple’s Screen Time feature, Cook admitted he was surprised by how much time he spent on his devices. Focus on a single task for 20 to 50 minutes. (Source: Freepik) Focus on a single task for 20 to 50 minutes. Do one task at a time: Focus on a single task for 20 to 50 minutes then take a short break and then again focus on the single task.