When most people think of on-call jobs, medical professionals and first responders typically come to mind. For first responders, like firefighters and EMTs, on-call usually means you are sleeping at the station, ready to wake up and respond to a call quickly. Medical workers, on the other hand, may work a more traditional on-call schedule. While some nurses and doctors may sleep at the hospital, especially during their residency, you may also have an on-call shift where you can leave and go home, potentially never actually coming back. If you want a career as a nurse or doctor but do not like this unpredictability, rest assured that the chance of having on-call shifts decreases as you gain seniority and advanced qualifications. Repair workers like electricians may also work on-call. You may occasionally find on-call jobs in retail or customer service sectors, but this is not as common.