Amsoil says 25,000 for their top formula (17,000 if you have forced induction or other ‘extreme’ situation.)

I have three cars (family caretaker) and I run them all on synthetic motor oil. One of them nears 20,000 miles per year. They all get an annual SYNTHETIC OIL change with extended drain interval filter. I’ve run Amsoil synthetic in all my vehicles for over 10 years now. Two of them are just under 200,000 miles (~196k…