You can learn to wing it with enough practice if you cook a limited number of things and do it the same every time on the same heat source. But if you throw in variables like charcoal, cooking in various weather conditions outdoors, or want to cook everything perfectly no matter whether you're frying or roasting, a thermometer is a way to get it perfect every single time without any guesswork or food poisoning.
You can err on the side of rare with a steak. Fine. But try that with a whole chicken. If you're guessing, you damn well better err on the side of well done (in other words, tough and dry). It needs to be 160-165, but it continues to rise about 5 degrees after you pull it out, so I aim for 155. If it's cooler, you risk salmonella; if it gets into the 170s, you've wasted a couple hours on less than perfect chicken. Can you tell if a whole chicken is 155 by touching it or cutting into it? No. With a thermometer, you ride the razor's edge of perfection and food poisoning.
A must read! One of my favorite sites.
Joe Biden … putting the Dem in dementia since (at least) 2020.