http://www.emedicinehealth.com/articles/41273-7.asp
Keep condoms in a cool, dry place away from heat and sunlight, such as your bedroom night stand (not medicine cabinet).
Your wallet or car is too hot for storing condoms. If you do carry a condom in your wallet for convenience, replace it often. Opening and closing your wallet, not to mention the pressure from sitting on it, will weaken the condom. However, it’s better to use a condom that has been in your wallet for a long time than not to use one at