Not clearly defined in 17025 is the ability to avoid cross contamination and/or one test affecting another test. One big item to think about is not allowing customers to see other customers' products being tested if you allow clients to visit during the testing of their products. Another thing to think about is storage of equipment to prevent damage when not in use. Flow of materials coming into your facility - locked storage until the samples are processed to be tested, locked storage of samples waiting to be tested or in process of being tested, and finally the disposal of the tested samples - tied into the concept of and potential clients visiting. Tied with that the desk areas for the engineers and technicians having locked computers and locked drawers to hide items that others are not allowed to see.