Originally Posted by Bicycle Helmet Safety Institute

Occasionally somebody spreads rumors that sweat and ultraviolet (UV) exposure will cause your helmet to degrade. Sweat will not do that. The standards do not permit manufacturers to make a helmet that degrades from sweat, and the EPS, EPP or EPU foam is remarkably unaffected by salt water. Your helmet will get a terminal case of grunge before it dies of sweat. UV can affect the strength of the shell material, though. Since helmets spend a lot of time in the sun, manufacturers usually put UV inhibitors in the plastic for their shells that control UV degradation. If your helmet is fading, maybe the UV inhibitors are failing, so you probably should replace it. Chances are it has seen an awful lot of sun to have that happen. Otherwise, try another brand next time and let us know what brand faded on you.

Originally Posted by Bicycle Helmet Safety Institute

Newer helmets from the late 1980's and the 90's may or may not need replacement. First look to see what standards sticker is inside. If it's ASTM or Snell, the helmet was designed to meet today's standards for impact protection, and you may even find that Consumer Reports tested it in one of their articles. Most manufacturers now recommend that helmets be replaced after five years, but some of that may be just marketing. (Bell now recommends every three years, which seems to us too short. They base it partially on updating your helmet technology, but they have not been improving their helmets that much over three year periods, and we consider some of their helmets since the late 1990's to be a step backwards, so we would take that with a grain of salt.) Deterioration depends on usage, care, and abuse. But if you ride thousands of miles every year, five years may be a realistic estimate of helmet life.

Originally Posted by recursive (Post 5031487)

I haven't experienced this, but it sounds quite obvious that you need a new helmet.

Originally Posted by BoSoxYacht (Post 5030738)

Do helmets break down over time, from sweat or hair gel? The inside of my Bell Influx(the structural foam) seems to be deterioating. Any surface that is incontact with my head, is getting soft and spongy.