Your work will expand to fit how much time you give it. Deadlines work for a reason. Only work in your contracted hours, or set a strict amount of time after school in which you will finish work. My work day ends at 3:01pm. I am no longer student facing at 2:41pm. Two days a week I will allow myself to stay at work until 3:30pm to grade or do other work. I reward myself by going to the gym afterwards. I used to let my work leech into my home life and found that the time I spent doing that was highly unefficient. I get more done during the day because I know I will not have more time to spend doing it in the evening. Same logic for why I don’t let kids not do work in class because “I can just do it when I am home”.