You are right ispud. The NEW engine parts need to have some friction in order to "seat" or wear in. Full synth is too slick for any of that initial wear to occur. Thats where the benefit of swapping out for it comes in. There will be almost zero wear after using full synth. I have run different brands over the years, and have my personal favs. but any of the top dogs will do. My engines are 2 stroke on my scoots. so I only have gear oil, fork oil, and 2t oil to deal w/. In my cars/trucks, I have always used full synth. for all the components. I have posted here before that the only oil related failure I have had in the past 20+ years was w/ an organic 2t oil. In my opinion full synth is the best preventative measure you can take.