- The helmet was subjected to an impact.
- The comfort padding or the retention system has become loose due to heavy use or display signs of deterioration. Test: with the retention system fastened, the helmet turns to the side when you gently shake your head.
- The EPS liner has come away from the helmet shell.
- The EPS liner shows signs of wear and is beginning to break up, or if it has been exposed to heat or a solvent and has melted. Or if there are indentations in the EPS liner and/or white scratches can be seen on surfaces with black paint.
Even if none of these factors apply, most leading helmet manufacturers recommend replacement 5 to 7 YEARS AFTER RETAIL PURCHASE.