They usually say that you can only use one per table, per visit and you are only supposed to use one certificate per month at each restaurant. We have never tried to use them any differently but wondered if it was possible. For instance, we thought about buying some for our grown kids but if we use one at a restaurant during a certain month and then they go to use one that we bought them, is it going to knock them out of using it? Don't know, and we haven't found the answer on their website.