When is it time to replace a helmet

[newkid900]

I have had my K2 hemet for years. It is in great condition with no cracks or damage and has treated me well. I'm curious at what point should I be thinking about replacing it? I have had it close to a decade now and I have heard the foam starts to harden after a few seasons. Does anybody have any advice on this?

 

[PaulBieterman]

always heard 3-5 years, mostly due to the plastic slowly degrading and weakening with temp changes. not sure how valid that is, but it made sense

 

[JulianSharpe]

Bike manufacturers recommend between 5-7 years. But obviously if you've taken any slams to it you should technically replace it there and then.

 

[freeskibum82]

there is a date sticker inside the helmet when it was produced. add 3 - 5 years to that (depending on manufacturer) and its time to replace. Anytime you've had a serious impact to it as well. the heating (bringing it indoors) and cooling (using it outside) cause changes to the foam and plastics. With how cheap helmets are ~$100-$200, is saving $40-$50 a year worth the risk?