My mother has difficulty keeping track of which key is for which door in the house and is very frustrated and it begins to frustrate me. I decided to get Mason to come and change all the locks in my house for me so that I would have two keys - one for the exterior and one for the interior. Now my mother only needs to carry 2 keys and remember which one is which. Mason kindly gave me two colored key chains so my mother can differentiate between the two of them. I am very satisfied and would recommend this company to my mother!