Millions of stamp collectors worldwide maintain new issue subscription services. Postal agencies avidly promote such subscriptions, where a collector signs up, lists his credit card, and then receives all of the new issues of the agency as they are issued. The price is usually face value plus a service fee and often, for foreign stamps, a shipping charge. The advantage of buying stamps this way is that you never miss a new issue; the disadvantage is that you almost immediately see a 50-75% reduction in the value of your stamps. This is because almost no one ever uses newer issues, at least not in the quantity that they are bought. When these newer issues are traded, they sell usually for half the postage value or less. So a wise collector would endure a little inconvenience and purchase newer issues a few years after they come out and save a great deal of money.