I'll second that. My rule is, after I think I'm ready to go, I walk around the entire rig, starting at the driver's door and finishing at the driver's door, checking everything (partly with eyes, partly by touching). If something had been left un-done, I do it, and complete the circuit, but I don't drive off just yet. I always need to complete a totally "clean" walk around before I get in and drive off. I pay particular attention to "nothing touching the ground except wheels", nothing hanging down or protruding, hitch secured and locked, chains crossed and secured, parking lights and hazard lights working. And when we stop for rest or for a meal on the road, before we drive off again, I do another quick walk-around.