I'm not saying I never change my oil, but every other ride seems a little excessive. I know what clutch matierial and metal looks like in oil, and I know when my oil is clean. Whenever I ride through deep water or mud, or ride in extremely dusty conditions, YES I change my oil afterwards.
I used to use golden spectro 4, but now I use valvoline ATV oil, which is designed for wet clutches. Shifts real smooth. Every other change, I add a little lucas additive.