Titles are helpful, but sometimes confusing. They are respectful, and can actually make situations less confusing or awkward, when used correctly. When used incorrectly, they can be your worst nightmare. So, I’m going to quickly overview the simplest, everyday titles, and explain (very briefly) how to use them.
So, first things first:
Mr. (Plural, Messrs.)
This can be used to address or refer to single or married men, in conjunction with their last names. If, however, you know that the man to whom you are speaking has another title (“Dr.”, “Rev.”, etc.), it may be wise to use it instead. If you do not know whether or not he has another title, always use “Mr.”.