Even medical doctors seldom use the title “Doctor” in a non-medical setting. I work in health care, and deal with plenty of medical doctors. Some of them, I’m also personal friends with. At work, I refer to them as “Doctor”. But in a social setting, I refer to them by their name. I have a friend, who is a nationally known physician, medical expert, and educator, whom I know mostly through an antique car club. Without calling him out, let’s say his name is Dr. Sam Smith. I attended a medical conference where he was lecturing. Before his presentation, I was talking with my good friend, Sam, about family and cars. But as the time approached, my friend Sam said he needed to get ready, and I said I’d take my seat in the lecture hall. Sam said, “You don’t have to stay because we’re friends.” I reminded him, “No, I want to stay to learn from Dr. Smith, top in his field.” His title was not appropriate in my garage, but certainly so in a medical lecture.