One of the most secure locks, deadbolts offer you home safety (and, sometimes, a discount on home insurance). However, it may be worthwhile to get a locksmith to install one. Up to 10 percent of deadbolts are installed incorrectly, putting you at risk for break-ins. [CBS Chicago] Make sure your deadbolt is A-OK by closing and locking your door. Draw a line to mark the point on the lock. Now, open the door and extend your lock. Compare it to the line you drew to make sure your lock is fully extended when you bolt your doors. If they don't match up, it's time for a new lock.