If you're like me you never have your business cards when you really need them. You might have a card case, but how often do you carry that with you when you're not headed to a business function? Carrying them in your wallet doesn't work; it doesn't take long before they're mangled from the heat and weight of being below you all the time.
But, there's an easy solution. You always have your phone on you, so stash a few on the inside of your phone case. The phone keeps them flat, and the ink doesn't wear. You could buy a special phone case like this one that has a built-in storage area, but why spend more money? I've been testing this for a couple of months, and it not only maintains the condition of the cards, it's saved me a few times already.