Well on my own personal '08 M1000 i havn't had it apart in a couple years. I also change the oil every season. The thing to watch for is when you cahnge the oil if you have any filings in the oil. If you do then pull it apart and inspect things for wear. You will usually get a little bit of really fine metallic lookin stuff in the oil and that is normal. But i dont think that it needs to be taken apart just to llok at it. I have like 5700km on my sled.