Now its never a good idea to hide a spare key outside your home! If you do never hide your door key under the mat! You’re really not the first person to think of that hiding place. If a criminal wants to access your home, they will usually search obvious places in the 10 feet surrounding your door. Doormats, pots, planters, mailboxes, rocks, and fake rocks are all common hiding places. Choose somewhere 15-20 feet away from the door that is unusual and protective instead. Or better yet, give your spare key to a friend or loyal neighbor!