I run BSD front and rear and they look almost new. Mind you, I am not hard on my bike and ride 99 % bowl and vert.
My rear plastic guard looks brand new but for some reason slows the hub down when its installed even though I cant see it rubbing...
I thus ride only the inner. I switched to the cymbal guard on my freecoaster as using a aluminium one made me have to hire Hulk Hogan each time I had to take the Wheel apart. I had to spread the dropouts out more than [insert any pornstar's name] to make it fit.