Some people like to baste every 45 minutes to an hour. However, you don’t want to open the oven door too often, as that lets heat out and slows down the cooking process. Depending on the size of the turkey and how long you’ll be roasting it, you can go with every hour and 20 minutes to every 90 minutes. If you’re cooking a smaller turkey or just a turkey breast, you should baste every hour.