Here are a few ways that help you know when to replace the old locks with the new one for your safety and security. Change the locks of all doors when you’re buying an old home why because we don’t know who all has the keys to the locks. So, to prevent an unexpected break-in by simply replacing all the locks. Thieves find easier to pick the imperfect lock like rusty or worn out lock on the door. In case, if you find still difficulty to turn after oiling the lock then you need to replace the lock for your home security. When an intruder breaks into the residence then you need to install a new lock. The door and lock are damaged from the sheer force that caused by the intrusion. Door without deadbolts are just like an open invitation to devious intruders. So, it’s best to install the deadbolts.