Where to measure
Take the centre of the thickest part, avoiding bone and fat. Bone reads hotter than the meat around it and fat reads cooler. Push the probe in and withdraw it slowly — the lowest reading you find is the centre.
Thin cuts make a thermometer meaningless: if the meat is thinner than the probe, you cannot measure it accurately. Judge those by time and feel.
Why you pull it 3–5°C early
Heat at the surface keeps moving inward after you take the food off, so the core climbs a few more degrees — carryover cooking. The thicker the cut, the bigger the rise. Not accounting for it is why meat comes out one stage more done than intended. Full explanation in Cooking meat.
What temperature cannot tell you
Collagen-rich cuts — short rib, shin, collar, belly — have no target temperature. You judge them by whether a fork slides in without resistance. One hour and three hours at the same temperature give completely different results, which a thermometer cannot distinguish. See Braising.
Food safety figures
Chicken 74°C, minced meat 71°C and pork 63°C are the safety numbers. The surface of a whole cut gets sterilised by heat, but mincing mixes surface bacteria all the way through, so mince has to be cooked through. Same reason a steak can be rare and a burger patty should not be.
Check your thermometer occasionally: 0°C in iced water, 100°C in boiling water (slightly lower at altitude).