I teach college freshmen. Roughly 20% of the people in my classes will be dropping out within the first two semesters, and I see no point in catering to them. I aim for the ones who are actually capable of college-level work.
In assignments, I generally think of the second and third quartile. But in lecture/discussion, I try to range up and down – restating the obvious on the main points, but also throwing a few things out there that I know 80% of them won’t catch. Frankly, if I don’t do a bit of the latter, the class bores me.