Interesting . . . I use single-spacing if it is up to me, but I had a summer internship where I had to use double-spacing (it also required Word Perfect--yuck). Honestly, it's probably better to get in the habit of using two spaces, because it is very easy to edit a paper from double-spaces to single-spaces. All one has to do is to use the find/replace feature--find [double space] and replace with [single space].