Today my helper and I wired two separate additions on the same building. one large office area and one small dark room for processing film and he asked me why some areas I'll run mc for switch drops and outlets and sometimes i run emt and turn out 90s I was wondering how some of you guys would answer this question my answer to him was depending on how fast I needed to rough a room in for Sheetrock turning 90s is faster but for less work after Sheetrock I would run mc and tie in all the boxes so the only thing left would be to bring a feed whip up to the ceiling and tying it into a junction box fed with pipe later on.