Question: How Do I Know When My Turkey Is Done?
Answer: The rule is that every ounce of meat in your turkey must reach a minimum of 165 degrees F. (74 degrees C.). Measure this temperature in the thickest part of the breast and the thigh, just above the drumstick. If you don't reach this temperature you run the risk of giving your guests a very good reason not to go to work for several days.
By the time the breast meat reaches this magic temperature the dark meat will be 180 degrees F. (82 degrees C.). It is good to measure this temperature as well to be on the safe side. Measure the temperature of the dark meat in the center of the thigh.
What you also want to look for is that all juices running from the meat everywhere is clear, unless you have smoked the turkey (smoked meats remain pink due to nitrates in the smoke).
The temperature difference between the dark and white meat means that the dark meat tends to get over cooked. You can fix this little problem if you understand the science of turkey.