You never know when you will be asked, "Did you do a pre-trip?" And if it's a DOT officer, you want to know if you looked good at the inspection date, the lights, the tires, the pins, fifth wheel, lights and even the valve stem covers. I'm picky about them and keep plenty extra in my side pocket door. A story from my first year of trucking really drove home that point: We ran into an old friend, and he had just picked up a load in which he needed to put a valve stem cover on all eight trailer tires. Again, thank you, David Dandeneau, for your wisdom and an important reminder! I won’t ever forget that, and Maintenance is glad to accommodate drivers with free valve stem covers and extra lights.