To be honest, a large portion of locks bought from home improvement stores are not installed correctly. If your lock jiggles, or has play in it at all, it is not installed 100% correctly. These kind of oversights make it easy for thieves to easily break your lock to gain access to your home, or invade your residence while your asleep. A honest locksmith won't leave a job until the lock is installed right and tight.
They will provide effective security to your home since their services are of high quality. When you go on a vacation for a long period of time and you have no choice but to leave your house unattended, you will have peace of mind because you know that it has an efficient security system installed by your local locksmith etc. If you are in wimbledon then Kings Security is the best locksmith.