Main Motorcycle: Speed Triple 955i ('02)
Join Date: Dec 2012
Service manuals mostly require oil change at certain mileage or time period, whichever comes first. Some manuals also state that used in "severe conditions" (mostly rainy, dusty, etc.) then more frequent change recommended.
Since my exR1, I mostly use adequate, but relative cheap heavy duty oils, and I aim for 4000 km change intervals - my motto here that a high grade, cheap fresh oil is better in the engine than a pricey one for the recommended (manual) mileage.
(If money wouldn't matter, then I would drain & clean my engine oil with an external centrifugal oil cleaning system (one micron filtration), then have it analysed by a lab and reuse if it's clean enough and up to specs. With a fleet I would go in that direction.)