When you book a place in a hotel or restaurant, confirmation is what they must do. It is part of the company operational standards that must be carried out primarily by employees of the company, as well as a way so that you do not lose your table or room of your order.
Reply Card or Envelope?
Instead of including a reply card or second envelope with your invitation, consider asking all (or at some) of your guests to RSVP online or via the telephone. This will save you a little money in terms of postage, reply cards, and envelopes; but it also reduces paper waste and clutter on your end. You will have tons of papers from various places that you don’t really need reply cards to help you become more confused. When you get the cards you will likely enter them into an Excel spreadsheet and then discard the cards, so skip the cards entirely!
By Phone or Email?
Most folks usually have access to a computer and can shoot off an email (or if you are computer savvy you can setup a form online that they can access). If they don’t have access to a computer, not entirely uncommon, then a telephone call is possible too. If you don’t want to force your guests to call you, then you can always just add a reply card to a smaller subset of your guests that you think won’t have easy computer access.
You won’t save a ton of money on this, probably less than $50, but every little bit counts!