I do have to choose among rules. The choices that I make are also a signal. I am an American, and I work in a profession where writing is important. I try to make style and grammar choices that match those of well-thought-of American writers in my profession. I do try to avoid choices that might make some people think I don't know the "correct" definitions of words (nauseous vs. nauseated, for example). I don't care as much about "will" and "shall," because American writers I respect mostly use "will," unless they are writing statutes or contracts. Also, I try never to correct other people; I am not much of a prescriptivist.