Because few recipes include the instruction “Cook until XX temperature is reached” only 20% of cooks regularly use a food thermometer. Heat kills harmful organisms and the eyeball method for doneness is not the best approach.
Roasts, steaks and chops should be cooked to 145 degrees F.
Ground meat 160 F.
Poultry 165 F.
Leftovers 165 F.
Finfish 145 F.