The wallet: home to money, ID and other useful stuff that most people don't leave home without – which makes it seem like a brilliant place to stow an emergency condom. But walking around with a wallet full of condoms isn't smart. Especially if they're in a back pocket, wallets are also home to friction, heat and pressure. All three make latex weaker, so wallet-stored condoms are some of the least reliable.
This rule goes double for glove compartments (and anyplace else that's subject to extreme temperatures). Just like candles, red wine and oral contraceptives, condoms should be stored in a cool, dry place.