Update: A retired tech told me my dryer vent checks were backwards, and it made my callbacks drop
Six weeks ago an old timer at the supply house on 5th watched me load up 4 inch flex and just shook his head at me. He said I was checking airflow at the wrong end and that I should be reading it at the outside hood first before I even pull the machine out. I tried it on my next 3 calls and 2 of them had birds nests blocking the whole run, which I would have missed poking around inside. My callback rate on dryers went from about 1 in 5 down to 1 in 12 over the next month. It takes me an extra 4 minutes per job but it saves me a whole second trip most days. Anyone else got a weird order of operations they stick to that sounds dumb but works?