Back in the mid 90's a buddy of mine went to work for Texaco at their plant out on the Houston Ship Channel. I was a Havoline guy for years. Havoline seemed to fall out of favor and got hard to find, so I switched to Valvoline sometime between 15 and 20 years ago. Now, I'm just trying to find the next "go to".I always used conventional valvoline in everything too until it became almost impossible to find in 5w-20 in my area. I switched my high mileage vehicles to their high mile synthetic and I’ve noticed less consumption since. My truck gets changed every 3k and my DD every 6ish.