I am a physics major and I have taken many math courses, but not Complex Variables. I did a little contour integration along time ago, but I never took it as a course. I do, however, have the option to take this semester. Should I take it instead of another physics elective? I know that it is quite useful for advanced quantum, QFT, etc., but how important would you say it is to take it as a course (as opposed to just learning the techniques as the need arises).