A simple trick I learned long ago that is super simple but can tell you A LOT about your CVT.
GET, GY6, anything with a CVT
-Remove your drive face
-Take a Sharpie and color a nice fat line on the belt side
-Install drive face
-Go cruising untill you feel you have maxed out your CVT (top speed)
-Remove drive face and see how much marker is still visible.
The higher up is worn off the more of your Variator you used. The higher up you GET the more speed you GET.