Before you leave on your wonderful journey, gather your address book together with some small to average size, peel and stick address labels. Fill them out with all the names and addresses that you wish to send postcards to from places visited and mark them USA. With this having been done at home, while you are on your trip you don't have to carry your address book with you or waste your time deciding who to send to or taking the time to fill them out with names and addresses in your hotel room! It also helps as you now know how many postcards you need to purchase. It really is a big help and one other thing that you can do ahead of time while you are anxiously awaiting your newest adventure!!
HAPPY TRAVELS!! (*_*)