I carry my SM card but don't think I've ever taken it out of my wallet. Just recently I discovered CardStar, an app for the iPhone (and I think Android). It's the greatest! You can scan all of your airline/hotel/car rental/AAA/Best Buy/etc. cards into its database and it will then display bar codes and/or numbers on the screen for scanning or just getting the number. It took me about half an hour to scan in about 60 various cards. It's free. Everybody I've recommended it to swears by it.