Now that I'm a PhD student, professors are going to become colleagues before now. That's part of the training process. But for now, how do I address them? I have one friend who errs on the side of extreme formality, (always "Professor A...") but that usually feels stilted to me. Another complication with it is that not everyone who teaches both undergraduates and graduates finds their primary identify in being a teacher (i.e. they may feel no more comfortable being called "Professor" than I do calling them thus.) First names feel too informal, and while first-name-plus- last-name works fine for introductions, it's no way to refer to someone to their face. It seems excessive to ask everyone I meet how they wish to be addressed - although it would certainly clear up the issue quite directly - especially since then I would be obliged to remember exactly how each and every individual academic I ever meet in the future has requested I address them, especially under formal circumstances.
How have any of you dealt with this?