If you're trying to avoid a Costanza-sized wallet, and you routinely travel by car, you may wish to consider creating a second wallet to hold all of your store loyalty cards and other miscellaneous wallet items that you don't use everyday.
Photo by Chanel Beck.
Household blog Unclutterer suggests you put all of these cards in a cheap wallet and leave that wallet in your glove compartment. This allows you to carry a smaller primary wallet without these cards you don't use on a daily basis. Also consider adding an old photo ID, expired credit cards and a few bucks to have your second wallet serve double duty as mugger's wallet if you find yourself in a not-so-safe area.