I recently finished reading a story (Ayn Rand's We the Living) which, because of the period and the culture of the environment in which it described, did not shirk on reminding both the reader and the characters of every person's name and rank within the story itself. I think for that kind of piece, it worked very well even though it did get a bit tedious at times for me, as the reader, to wade through it. For that particular world and that particular culture, it made a lot of sense to do so, but I'm guessing that most of the time, it probably is not necessary. I've read plenty of stories in which such rigidity would have seemed overkill, but sometimes it fits the world of the story so well that, if it were absent, one would think something was definitely missing.

I guess what I'm saying is that it depends a lot on the specific story, the period and culture of the story, and the characters you are working with. Heck, I could envision a character who might have a compulsion to call every person by their full name, and thats just who the character is.

In other words, don't worry so much about your reader. Worry about your story, and how you choose to identify your characters within the context of that story will practically work itself out.