Do you really need a meat thermometer?

I’ve never used one when cooking at home and I never owned one. I eat a little bit of the outside while cooking beef roast or chicken wings. Do I really need one? I eat alone so I am not hurting anyone other than myself. I just cooked, and ate, chicken wings without a meat thermometer at 4:20pm mountain standard time and i’m still fine. The first one was a bit tough and under cooked. Would it be safer if I ordered out KFC instead? I have half of a blade steak to cook and I could not eat it my teeth were hurting from the chewing.