When our home electrical box needed repairs - the main breaker was corroded; the system is over 25 years old and we thought we might have difficulty locating parts for repair of the system. My husband took an up close picture of the electrical panel; he took a ruler and photographed the ruler on certain areas of the system so electrical parts personnel could determine if they could supply us with the parts. The pictures were a success and the hardware store we found the parts at (the part had to be ordered) was very appreciative of the picture when he was in the process of ordering the part.
We have decided to take pictures of all the important components in our home (plumbing, electrical, septic tank, etc.) in order to have a visual record. These pictures will be kept in a file and will be updated when repairs or changes are made.