Very durable. Never had a shop fixed chip spread, though I got cheap and tried one of those do it yourself kits once...didn't work for me.
Got smashed with a rock once while driving my old Honda. Saw the rock coming, looked like it was about an inch...SMACK.. circulular crack looking like the sun with lots of rays coming off, full 2" diameter. Got it fixed, didn't figure it'd hold, but thought I'd try. Years later when I got rid of the car the cracks hadn't spread and you still couldn't see the repair unless you looked through it at an angle in bright light. Very impressive and durable.