I religiously change my car's oil twice a year. Usually it's done Spring and Fall, and that usually puts the change interval at 3,000 miles. Also, because the oil is always fresh I'm not one for additives, but that changed last week. This time I added Schaeffer's Moly EP Oil Treatment to the crank case, and Holy Cow the engine is now very quiet, smooth and I will also say robust!. I don't know why I picked this additive but I'm glad I did.
https://www.schaefferoil.com/documents/37-132-td.pdf
https://www.schaefferoil.com/documents/37-132-td.pdf