Originally Posted by
JohnJ80
...in the process of converting all our bike helmets over to MIPS this year as we go through the recommended replacement cycle on helmets due to age and usage.
Can you explain the rationale (besides marketing) for the so-called "recommended replacement cycle on helmets due to age and usage"? Is there any existing evidence of degradation in helmet effectiveness (such as it is) due to age or usage without visual indications of degradation?