When you purchased your home did you have the locks changed? Do you know who might have keys to your home? If you have not changed the locks to your home since you moved in you should consider having the locks re-keyed. This is a cost saving method of changing the parts inside your existing locks so the old key will no longer work and newly cut keys will now operate your locks.
It is not uncommon for the old home owners to have given out keys to your locks to neighbors,children or other family members as well as construction workers, house keepers and real estate agents, not to mention did they ever loose their keys?
For your family’s safety and your peace of mind please consider re-keying your homes locks if you are not 100 % sure who has copies of your keys.