Although the future tellers and magicians say cards (yes, paper cards) tend to dissapear, everyone still has paper cards and they are going to be used for a long time still. So, in the meantime get a card holder and organize them, or have yours neatly presented on your desktop. You never know when you are going to need them so you better have them handy.
This paper cards holder also works alright to storage your post-it notes.
try it! our desktops are so much cleaner since we printed some...