some people don't know when to quit
some people (just) don't know when to quitand some people (just) don't know when to give up; some people (just) don't know when to stop
1. You, or someone being talked about, should stop doing something, such as talking, arguing, scolding, etc. (often directed toward the person being addressed.) Bill: I hate to say it again, but that lipstick is all wrong for you. It brings out the wrong color in your eyes, and it makes your mouth larger than it really is. Jane: Oh, stop, stop! That's enough! Some people just don't know when to quit. John: Those bushes out in the backyard need trimming. Sally: You keep criticizing! Is there no end to it? Some people don't know when to stop!
2. Some people do not know when to slow down and stop working so hard. Jane: He just kept on gambling. Finally, he had no money left. Sally: Some people don't know when to quit.