I do yearly oil changes since I ride multiple bikes that change in any given year. When one breaks I transfer insurance and plates to another one. This year it will be the S4RS and Busa. The thing with the oil is, I’m usually not that picky at all, I will buy whatever good oil is cheaper. It’s only that I noticed the shifting difference that I have a preference for Motul. That’s what I use in the Ducatis and Busa . I use HD synthetic in the DynaGlide, and whatever is around in everything else. Once a year, unless I don’t.