The most important meal of the year for some is also the easiest. Before you roast, you might need to thaw. Thaw the bird slowly in the refrigerator. Allow one day in the refrigerator for every 5 pounds of turkey, then add an extra day. Change water every 30 minutes to keep it cool enough to prevent bacterial growth.
Time is the only variable.
Use a per-pound chart to help you plan the timing of your other dinner dishes, but for perfect meat, use a meat thermometer. If you use a traditional thermometer that goes into the oven with the bird, place it in the thickest part of the thigh, not touching the bone. If you use an instant-read thermometer, remove the meat from the oven before you test the temperature, either in the thigh or in the thickest part of the breast. The thigh should register 180 degrees, the breast meat 170. 2 to 3 days 6 to 9 hours 16 to 20 lbs.