For a lot of programs, you're supposed to ask for recommendations from 3 different professors. In an ideal situation, one could develop close relationships with 3 different professors, but that usually doesn't happen. So, I'm thinking, how well should I (or anyone else) know a professor before asking for a rec? Would stopping by for office hours a few times in the quarter be enough (is this how a lot of people know 1-2 of the profs they asked for recs from?). If I'm, say, asking for a rec from a professor I took a class in, what sort of grades should I get in that class before asking for a rec? (of course, a really good rec could come from a prof who gave a B to a student, although those cases are probably rare and would demand exceptional effort on part of the student, and would demonstrate the student's curiosity+conscientiousness more than talent). Of course, I'd imagine that students have varying experiences with each prof, so one prof's rec could highlight intelligence, one could highlight hard-working-ness, etc... Thanks!