My home was built in 1957 by a plumber. A basic alarm system was installed but disconnected three owners later. ADT was able to reuse components of that system and reactivate a motion detector and sensors. This saved me hundreds of dollars but allowed me to create 4 more alarm zones for free. On a return visit four years later with all new people, the technician charged me for reinstalling an alarm on a replaced door but, charged me the labor only and reused components from the older box on the door and provided me with another key fob reprogrammed with my new codes at no additional charge.