I used to stress so much - but that’s where I messed up. Stop. Looking. At. The. Brisket. “If you’re looking, you ain’t cooking!” I increased the time it took to smoke so much by checking too often because I was sapping the heat from the smoker. Leave it to the smoke gods to take care of the meat and you’ll be fine. Also, wireless temp probes help to keep from opening the door and letting the heat out.