I ran Amsoil for years and the only reason I stopped is I moved to the UK and cant get it here. I ran it for the 12 months /25K and changed my filter every 6 months. I ran the ass off of the car, it still looks new inside the valve cover after 6 years. I swear by it Of course that is just my opinion others may differ. I would only use/lose 1 qt in a year including the 1/2 qt to replace what was in the filter.