Oh great reason. And all the engines people run up to 300k miles without synthetic. Explain those?
How about the 50+ year old tractors on our farm we don't run synthetic in that are still working fine and see more stress in one year than majority of vehicles on the road see in 10. Synthetic has its benefits. But when I'm changing my oil every 5k miles why should I bother with the money? When I bought my truck I asked about oil and they said I could run any brand as long as it had the correct weight and proper change intervals and it wouldn't void my warranty. That was straight from the tech. Ford doesn't even use a full synthetic oil. Its a semi synthetic.
I just never bought into all the oil hype. My familys run many many many vehicles into the ground from rust and never used synthetic oil. Hundreds of thousands of miles. Myself, I've owned only 4 vehicles so far but never had a problem with quaker state. what I WOULD like to try is the Valvoline NextGen. But its damn expensive.
^^This is why I said as long as you change it regularly, it doesn't matter what you use, as long as it's the correct viscosity. There are millions of engines with well over 200k miles on them using nothing but the cheapest conventional oil.
Some engines (not Ranger engines) REQUIRE synthetic, because either the automaker specifies long oil change intervals, or the engine gets the oil really hot and synthetic handles the high heat better. In those cases of course you should use synthetic.
If your engine does NOT require synthetic (Ranger engines): If you plan on going over 7k miles between oil changes, or if you're beating the hell out of the truck in extremely high or extremely low temperatures, you should use synthetic. Otherwise it is not needed, and it will NOT help your engine last longer.
If you would just like to think that it WILL give you some benefit and want to use synthetic anyway just for some peace of mind
(which is why I use it), then I suppose that qualifies as another legitimate reason to use it.