on the Downtown and GTi, a belt change is recommended at 12,000 miles. I think most riders like to change rollers/sliders at that interval. Some go longer.
I pulled my GTi down at 10,000+ miles and was glad I did. It was really dirty in there and the belt showed wear. I cleaned, changed belt and added sliders.
For me, I plan the clean and change everything at 10,000+ miles. Don`t want a failure 100 miles from home.