My way to cope with it: I work on the task as much as I want to, I even create the responding email, but I’m not sending it before the next workday. This way, I feel satisfied but not taken advantage of. On the next workday, I’m already one step ahead, which makes a good start. And I get fewer and fewer requests in my free time because no one is used to me working then. If people want me to answer the same day, they hurry to ask me earlier.
So this is my Tipp: don’t answer emails at night or on weekends. Work on them if you want, but whatever you do, don’t hit send.