That isn't much of a solution in practice. No helmet manufacturer puts best after dates, other than in fine print nobody reads and practically nobody replaces helmets unless they see visible damage.
Then again 3cm of expanded polystyrene foam vs a metal box with a engine in it... probably like a surfer forgetting to replace their “anti-shark bite” medallion anyway.
Then again 3cm of expanded polystyrene foam vs a metal box with a engine in it... probably like a surfer forgetting to replace their “anti-shark bite” medallion anyway.