Should you baste your turkey while it bakes?
If you are basting the turkey in an effort to make the meat juicier, you are probably wasting your time. Basting the turkey has little if any effect upon the moistness of the meat. It will mainly cause the skin to brown up a little more crisply, and may add some extra flavor to the skin. The skin is quite effective at blocking moisture, however, so don't expect any of the juices you baste over the turkey to seep down into the meat.
The moistness of the meat is primarily determined by cooking to the proper temperature. An overcooked turkey is going to be dry... that's just the way it is. You can do some things before roasting that will influence the final outcome more effectively than basting. Brining the turkey -- soaking it overnight in a salty, seasoned liquid -- will add saltiness to the flavor, but it will also cause the turkey to retain more moisture while it roasts, meaning a less-dry turkey.
Alternatively, a light coating of kosher salt on the inside of the turkey's cavities before going in the oven will have a similar effect, helping the bird to retain moisture during roasting.
Finally, a kosher turkey, which has been treated with salt as part of the koshering process, will likewise retain more moisture while cooking due to the salt content.
The downside to basting is that each time you open the oven, heat is escaping, meaning that the time to roast the bird increases, and the oscillating temperature in the oven may lead to a less satisfactory, evenly-cooked turkey. As an alternative to basting, you can apply a light coating of cooking oil to the turkey's skin before it goes in the oven. This will help produce the same sort of nicely crispy skin that basting does, without periodically opening the oven door during roasting.