It’s your best shot at getting guests to RSVP.
With the popularity of email, texting, and automatic bill paying, having postage stamps on hand is becoming less and less common. When someone needs a stamp, this scenario is common: They scourge around looking in drawers and in their wallet, and then (hopefully) mooch one off their coworker. When your guests receive your wedding invitation, make it easy for them to RSVP by having a stamp already on the card. If your address is included, too, they have no excuse not to drop the card in the mail right away. If you know your guests are still going to want a digital option, provide a link to the RSVP field of your wedding website on the note.