Tell me you're joking! Maybe if I was getting married in my backyard with a guest list of 20 people, I might consider phone calls. But a hundred? Silly rabbit.
We're picking up our invitations tonight, I'll post a pic of what I'm talking about. They aren't engraved, they're printed. They are elegant but simple. We did not put any filler in. None of those see-through sheets that serve no purpose. An outside envelope with the return address on it, a plain white inside envelope (I didn't want this but in case of rain during delivery, it protects the stuff inside), the invite which is one sheet, no ribbons, no floofy stuff, the pre-addressed response envelope, the response card, and the directions.
Emailing is tacky and the amount of work involved with calling 100 people, giving them all the details and getting an answer on if they're coming is just crazy.