I’ve been an Amsoil Independent dealer for over 25 years because of my personal experience and based on numerous metal wear tests, Amsoil beats all other brands of synthetic motor oil. My personal experience has been that my vehicles have longer engine life, less wear, less maintenance, and better fuel mileage. Also a savings in money because of less oil changes. The Amsoil recommendation is to change the oil in vehicles once a year or every 25K miles under normal driving conditions. Severe conditions recommended oil change is every 15K. I would never go back to conventional petroleum oil!
Here’s a great article on the benefits of AMSOIL Synthetic Oil over Conventional Motor Oils.