I recomend using the card every time you cross into the U.S. As you're coming up to the booth just wave it in front of the white plastic thing and they will know who you are when you hit the window. You have to use it as part of a FAST load. If your PAPS fails and you have to go see the broker, you can use it to go to the front of the line at customs. Just ignore the glares from the others waiting, they should have gotten the card. You will also use it to clear CSA loads into Canada.