The standard recommendation for basting a turkey while roasting is about every 30 to 45 minutes. Basting this often helps maintain moisture and adds flavor without excessively prolonging the cooking time. Some sources suggest basting every hour to avoid losing too much heat from the oven, which can increase cooking time as well. If you choose to baste, do so quickly and efficiently, making sure to close the oven immediately to retain heat. Alternatively, some suggest basting only during the last hour of cooking or even as few as two to three times during the entire roasting process to prevent heat loss and a soggy skin. The optimal frequency depends on your turkey size, oven setup, and personal preference, but every 30 to 45 minutes is a common, balanced practice.

In summary: baste a turkey approximately every 30 to 45 minutes during roasting, but avoid opening the oven too often to maintain cooking temperature and achieve juicy, flavorful results.