Not many professional cook teams will be without a Thermapen...or something similar. But like other posts say, you may want to have a wired probe in the meat at all times for "in the ballpark" constant readings. Then when you think you need to uncover the WSM, probe with the pen as you get close to pull temps. If you are pulling the lid on and off to check with a pen, you lose too much heat. The old saying, if you are looking you ain't cookin. The wired probe keeps you honest.