<p>I think this is very regional, and that in some parts of the country these naming conventions are not as closely linked to showing respect as in others. In the South, where I grew up, the default was certainly to address anybody older than oneself as Mr. or Mrs. XXX. I once worked at a law firm in Norfolk, Virginia, in which many of the partners addressed the more senior partner as Mr. XXX. It didn’t seem strange at the time.</p>
<p>For young people reading this, I would suggest this takeaway: when interacting with older people, don’t assume that they will prefer to be on a first-name basis with you. Look for clues (like how they introduce themselves). If there’s no clue, I would suggest taking a conservative approach and addressing them more formally until they tell you they prefer something else. While some people may “feel old” if you call them “Mr. Smith,” that’s not as bad as the risk that Mr. Smith will think that you are showing him disrespect if you call him John.</p>