I change my oil in all three holes with the most expensive super duper synthetic after every ride so I know I'm getting the best possible lubrication and no contaminants in my bike. Anything less is considered abuse. It's cheap insurance so the oil companies never go out of business and leave us with no new oil. Sometimes, if the ride is more than 100 miles, I'll bring oil along and change it so as to not damage the extremely fragile Harley engine. So there!
Maybe, but trannys don't have any contaminants getting in there. Metal particles are picked up by magnetic drain plug. Primary just keeps clutch cool and lubes a CHAIN. Not too difficult. I go 5k as per manual, but I doubt it's needed as often except engine. My $.02 I gotta go change my oil. Got 550 miles in last weekend........