the mugs are the exact same ones, but i've seen people filling up 7-11 cups, empty water bottles, cups from other places and nobody says anything. i don't want to start another "mug war" but i reuse my mugs each trip. we were told when we purchased them that they were good for future trips & so i use them. the mugs that came out last year were the first ones with the "length of stay" printed on them. i say that if you bought your mug years ago and were told that they were good for future trips then it's a personal choice about whether or not to reuse your mug on subsequent trips.