As for my daily driver, every 3000 miles. Using Valvoline, car has 250k on it so far. My brother does the same and racked up 350k on his V-6 truck before he sold it. Never had any mechanical work done, except for a water pump.
When the 440-6 is done and broke in, I plan on Royal Purple. Change it every year whether it needs it or not. :thumbs:
P.G.