My fiance and I are addressing our save the dates this weekend, and my mother thinks they need to be worded in a formal manner (e.g. "Mr. and Mrs. Joe Smith" versus "Joe and Susan Smith"). While we'll obviously keep the titles more formal for our grandparents, older relatives, etc., I think it's completely appropriate for us to be a bit more informal with our friends and coworkers (we're all under 30). I'd love to hear others' thoughts on this topic. If you've already gotten married or are past the save the date point in your engagement, what did you do?