>>1613299based, I've replaced two helmets from bad crashes so far
First one was on a bmx going 30kph, hit a pole with the tip of my right bar, slid about 4m on my head, could barely walk afterwards.
Second was hitting a horizontal bar at dropout height ~20kph coz I wasn't looking where I was going, landed on my head hard, blacked out, split my lip, pretty sure I got some kind of concussion.
Wear your helmet folks.