Nothing brings back memories of a trip like receiving mail from friends you made while on vacation. If they don’t know how to contact you once you’ve left, though, you won’t be getting the piece of art they promised to send, their postcards, or their letters, so don’t forget to exchange your addresses (snail mail and email both) with new friends you meet and make while traveling. You’ll enjoy memories of that trip all over again when they contact you. If you’re lucky, you might even be invited back!