Fellers that have been cookin with open fire er coals fer many years can put there hand over it an tell ya pretty close what the temperature is.
I prefer to use a thermometer an turn out consistantly good Q. There is a difference between the proffesionals an those who are just learnin the craft. As has been said before, most, not all, of the factory original thermometers are incorrect. If you chose to use it, fine, the suggestion here is to know what yer tempertature is to eleminate either over cookin er undercookin. Or we can look at it this way, would ya drive a car without a speedometer, or one that wasn't accurate? It can be done, but it dosen't have to be done. Why not make life simpler fer ourselves ifin we can?
I choose ta know where my box temperature is at an that is done with a digital thermometer. Just my two coppers worth.