i've been running plastic pegs since about june 2014. i bought a set of 4 primo binary plastics, like 4.25 long, i know they make 4.5 long pegs which i regret not buying but they weren't available at the time. they come with an extra sleeve per peg. since i bought the pegs, i haven't broken or cracked a sleeve, which is always a good thing because i pretty much spend the majority of my time riding grinding stuff. i have yet to wear through the plastic and get to the aluminum core, but i do rotate my pegs putting my backs in the front and the fronts in the back. so i've successfully owned a set of 4 plastic pegs and by rotating them maybe 3 times i've had them last over 6 months. hopefully this helps. i'm thinking about ordering another set of 4 sleeves and replacing my current sleeves in the next month or two.