Be organized and keep track of details.
It's a good convenience, but don't lose your card's number. My fault for losing track, but one time, after not having the number, the system seemed to recognize the ID and apply it.  The next time, it wouldn't.  There's apparently a glitch in the tally of the current order, the amount of the previous one not being subtracted from the balance on the card. Maybe, because I didn't input the number, the transaction actually went through by reverting to a different listed card, but the checkout page said it was applying the gift card.
Rating: 5 stars