seal- hardly a chemical engineer, but I spent 30+ years working on turbine aircraft, where all lubes including engine and airframe were pure synthetics.

The new engine and trans oils, especially the pure synthetics, will give you much more protection than any dino oil, and for a much longer period. The changes are up to you, but I change filters much more often than oil on all of my vehicles as far as engines and trans are concerned.

Differentials, transfer cases, and power steering pumps will also suffer less wear using pure synthetics than dino-based oils or blends, as the synthetics won't absorb moisture and don't break down nearly at all with age, especially compared with dino oil.

Obviously, TN climate doesn't require nearly as much attention to viscosity as it does up here in the north, but longevity of the lubricant is still much longer in the other fluid parts of a vehicle if synthetics are used. I especially prefer Schaeffer or Royal Purple in the diffs, xfr, trans, and pwr steering pumps. I've experienced less noise, higher mpg's, and the peace of mind knowing I really don't need to address them for the rest of the life of the vehicle.
Jim