Leaving keys in the lock overnight may invite burglars, experts warn

If you leave the key in the lock overnight, thinking it will increase your safety, we have bad news for you. Unfortunately, you not only fail to protect your home, but you're also inviting thieves inside.

We all want to feel safe in our homes, especially while sleeping. Fearing break-ins, many people leave the key in the lock overnight. Unfortunately, instead of increasing their safety, they achieve the opposite effect.

Leaving the key in the lock makes it impossible for other household members to open the door from the other side using their key. Unfortunately, these are the only people for whom such a practice makes it difficult to get into the apartment.

In reality, leaving the key in the lock makes it easier for thieves to access your home, enabling them to use two methods: a lock pick or a "coat hanger trick." While the latter mainly threatens door owners with a mail slot, the lock pick is a problem everyone should fear.

Inside the lock are pins that release the lock only when pushed adequately by the key's grooves. Leaving the key in the lock overnight "disarms" the lock, making it easier for thieves. Now, they no longer need to maneuver a lock pick to find the right combination—you've done it for them. They must insert the lock pick and turn it to open the door, a task even a novice burglar can perform.

Although doors with mail slots are rare in the United States, some people have them. In such cases, thieves will check if you've left the key in the lock overnight. They use a wire hanger, similar to those you receive after picking up clothes from the dry cleaner.

Burglars insert the hanger through the mail slot and use the hook to grab the key. It's easiest if it's a bunch of keys, as they can catch the ring holding them. This requires some skill, but thieves often have it, so they quickly pull the key out of the lock and open the door, gaining access to your home.