Every time we have gotten the sticker they have written the dates of our trip on it so it would not be valid past the last day. Also as others have posted you must have the GAC with the stickers so they will give you a new one anyway. On our last trip the CMs where checking the GAC for the tag at almost every ride, at some rides they would check it when we got in the line and then check it again when there was a split off point, so be prepared to have it handy before going to a ride.