You are authorized a Post Office Box at the military postal facility. Your sponsor can reserve a box and give you the address as soon as your sponsor receives a copy of your PCS orders. This will enable you to do your “change of address” cards. As with any move, it takes a few weeks for any change to take effect with your correspondents and magazines so the sooner you send in your new address the less delay you will experience. Don't forget to put in a forwarding order with your United States Post Office if in the U.S. Under the Military Postal System (MPS), you and your correspondents use U.S. postage stamps and rates. The MPS moves mail to and from designated United States locations so you do not pay overseas mailing charges. A first class stamp gets letters to and from an overseas APO just as if you were still within the U.S. You will still receive any magazines, catalogs, and packages without having to pay international rates which is a big cost (and time) savings. Customs forms are required to send packages to and from APOs.