It's always a good idea to have a spare key available in case of emergencies, but hiding that key on your property is risky. Thieves know all of the usual hiding spots -- fake rocks, flower pots, under doormats and above doorframes. It's best to give your additional keys to a trusted neighbor or friend who lives nearby. If that's not an option, be sure to conceal the keys in an unusual spot that's not at the front of your house. Preferably, where no one can see you getting the keys.