Well actually I don't have a credit card at all. But I do have a card for my bank account, one for the library and serveral other cards of this size. I agree, some kind of holder is usefull, or in my case absolutely necessary. So many cards have cracked in my wallet. This days I carry them in a small metallic box designed for business cards. All my cards in just one box and no way of dirt getting in and scratching them. You know people are worried about having their blades scratched in kydex sheats? I think a little bit of dirt in this holder could do major damage to the card.
By the way...
Have you ever thought about making sheats for darts? I don't know if many people play darts in denmark but I made a kydex sheat for my darts and lots of other guys asked me to make one for them.
Chrisse