I personally keep 2 wallets, one small, one long. I use my long wallets daily though. I like having everything with me and my wallet is always full. Thank God my wallet (a bottega veneta zip in magnolia-pink!!) is a huge one and it fits everything! I find a small wallet useful for times when I want to use a small bag or like a clutch for evenings as I will feel insecure if I dont carry my wallet with me even though I will not be needing it on the occasion. I dont know whether the small wallet will fit in a clutch though.. oh well.. I'm no help.
But if I were you, and I have something else (like a clutch, or louboutin, or something) that I am eyeing for, then I would switch one wallet for that thing=) but I'm a little evil to my friends and bf.. haha