I haven't used Blackstone for quite a few years. Last samples I sent in were for an '01 Ford Windstar (which never had any real issues with) in 2012 and when I rode motorcycles. I may send in a sample for my Rav when it's time to change the oil again using OEM filter and Pennzoil Platinum full synthetic. Occasional oil analysis is always good to determine the health on an engine. We do regular oil sample analysis on the engines at our plant (Caterpillar V12 turbos).