Used to eyeball every sear on the flat top, now I use a $12 IR thermometer and my steaks come out the same every time | Chefs - The Design Community Hub
My grandpa did the same thing with his old charcoal grill, just held his hand over the grate and counted the seconds. He swore he could tell the temp within 10 degrees that way, and honestly he was pretty close most nights. Then one summer he got a cheap thermometer as a gift and found out he'd been cooking 75 degrees hotter than he thought for like 20 years. He was so mad about it he almost threw the thing in the trash, but his burgers quit coming out burnt after that so he came around.