When I went to purchase my Monster's Inc. DVD and card there I happened to run into the district manager and asked him about not using a rental every week. This is exactly what he told me: The rental cards work on a weekly basis but do not expire. If you do not use your rental for that week it will remain on your card. At the end of the ten weeks you will still be able to use the card with the remaining rentals at the rate of one per week. I had been reading about people who were worried about renting two movies per week because they had two cards. I hope this helps those in need.