How long depends on the engine, driving style and climate. PP is not formulated? or sold as a LLO. I would not do over 10K miles without a UOA. In reviewing many excellent PP 5K UOA, it appears that 8-10K may be the limit for most of us,
? or sold as a long-life oil and I would not go much over 10,000 miles without a UOA.