I start to check if the turkey is finished after about 2 hours of total time in the oven. I go off the temperature and then add on 15-30 more minutes depending on the first read. It is best to remove the turkey from the oven once it has hit 155-160 degrees. The turkey will continue to cook while resting and taking it out a bit early will ensure it doesn't get overdone. Once your turkey reaches that temperature you will need to let it rest for at least 30 minutes before you carve it.