Something to ponder for a Wednesday... This will take a few minutes, so go take a piss, get another cup of coffee and sit back... I have recently bought another new Arai helmet. It seems I am/was purchasing a new helmet every couple years or so. For whatever reason: wanted a new style, new color, better ventilation, etc, etc, etc. Previously I was spending 150$ or less per helmet. Since moving up in price and hopefully quality, crash-worthiness, etc my 500$ + lid should serve me for several years. NOTE::: I do not want to hear your dribble on why you would never buy a used helmet...and this is sort of the point on my post here...determining how to evaluate a used helmet. Remember as soon as you wear your brand new helmet on a ride..it is used!I have scoured the flea market for a used helmet to have as a spare for rough and tumble days as to prolong my new Arai lid a few more miles. I have fell into the trap of asking when was the helmet manufactured, how long have you owned it, any damage, and the usual other relevant questions. I say trap, but with a disclaimer...more on that in a bit. The rule-of-thumb is to replace a non-crashed helmet every 5 years... According to Web Bike World and the Snell Foundation: Why should you replace your helmet every five years? The five-year replacement recommendation is based on a consensus by both helmet manufacturers and the Snell Foundation. Glues, resins and other materials used in helmet production can affect liner materials. Hair oils, body fluids and cosmetics, as well as normal "wear and tear" all contribute to helmet degradation. Petroleum based products present in cleaners, paints, fuels and other commonly encountered materials may also degrade materials used in many helmets possibly degrading performance. Additionally, experience indicates there will be a noticeable improvement in the protective characteristic of helmets over a five-year period due to advances in materials, designs, production methods and the standards. Thus, the recommendation for five-year helmet replacement is a judgment call stemming from a prudent safety philosophy. I am going to break this statement down ---way down--- in a minute so bear with me while I throw some numbers in your face. That sounds reasonable enough on the onset but take into consideration a few items that may increase or reduce the "life" of a helmet. I preface my examples that are assumed the helmet has not been involved in any type of crash and been taken care of as any average motorcyclist should. Say for instance a helmet was manufactured in January 2007. With the "5 year plan" that helmet would, by default, be ready for the scrap heap by now. However, consider that the same helmet was made in 01/2007, sat in its original box on a shelf in a store or warehouse until 01/2008. So that's one year that the helmet was not in use or exposed to any perceivable damaging effects. Would this helmet have an extended life expectancy of greater than 5 years since the first year of its life was spend in isolation. Now take it a step further and look at the actual road (in use) hours of a helmet. I did some quick stats and figure I have my helmet on my 'noggin for nearly 700 hours per year. Taking into consideration that I ride/commute every day, all year plus weekend jaunts, and 4 weeks vacation time per year...I wear my helmet quite a bit in all types of weather. Now analyze a more typical rider and say he may wear his helmet 350 hours a year. He commutes to work only in the warmer months, April - October, and takes a two weekend rides per month and then one week with the boys per year. Let us call him Sam. Final example...a fair-weather rider and logs only 150 hours a year since he rides only on Saturday and Sunday during May - September when there is no chance of rain, and then only to the local beer joint and back home...a long day in the saddle for this guy is an hour. We will call him Joe. See...my point...???? There are too many variables, IMO, to have a blanket statement to scrap a helmet after 5 years. My 5 years will have a conservative 3500 hours versus Sam that may have only 1750 hours or even fair-weather Joe that has 750 hours. WOW!...I put nearly as many hours in one year than Joe does in five years. Now, I do realize that in theory, my 700 hours/year lid should be replaced more often than Joe's 150 h/y lid. But, conversely, in theory, shouldn't' Joe's lid last him much, much longer than mine...maybe 8-10 years? And what about Sam? Is he the typical rider that the "5 year plan" is relevant? So would more relevant questions to ask a initial owner about a used helmet be: How many hours have you worn the helmet? What are your riding styles? Dual Sport, Street, Track, Bar hopping, touring??? What bike do you ride? Where do you store the helmet when not in use? In its bag on a shelf? Thrown in the same garage corner where you store your lawn mower gas? In the attic where its 150Fin the summer and 20F in the winter? ...lost of variables come into play when determining the actual life of a helmet. I understand that the helmet manufacture folks are in the business of selling helmets. The Snell Foundation is not. I also understand that there has to be some "price-tag" put on the life expectancy of everything. Even an anvil will wear out sooner or later. Realistically, who keeps a helmet 5 years and then trashes it for a new one? Most of us...yours truly included...want newer, better, etc and will, most likely, buy a new lid before the 5 years are expired. But for the sake of argument...and back to my original point...what is the real life-expectancy of a helmet that has been taken care of? Now let me break down the statement I copied from the Snell Foundation web site. My break-down will be noted in yellow color font...hi-viz font...that is... The five-year replacement recommendation is based on a consensus by both helmet manufacturers and the Snell Foundation. Consensus according to Merriam-Webster: general agreement : unanimity; the judgment arrived at by most of those concerned : group solidarity in sentiment and belief. With consensus there is no scientific fact or basis. Consensus is just a group of people agreeing on an item. So the consensus is that Snell and the helmet mfgs agree to replace at 5 years. HMMM! Glues, resins and other materials used in helmet production can affect liner materials. Hair oils, body fluids and cosmetics, as well as normal "wear and tear" all contribute to helmet degradation. Petroleum based products present in cleaners, paints, fuels and other commonly encountered materials may also degrade materials used in many helmets possibly degrading performance. This makes sense and I agree (this part has my consensus). However there is no backing data to support this statement either. "Possibly" degrading performance...shit a brick, I could possibly fly to the moon if I had a rocket on my back. This, IMO, is where I would like to see some data to back up this statement. Do a test on Joe's helmet after 5 years and compare it to mine. See if mine had degraded more. In theory my helmet, if based on this statement, should be ready for the sanitation department after only a couple years as compared to Joe's helmet that may last into the next decade. And would a female rider's helmet have be more degraded since she may have hair care products, make-up, perfume, etc, etc, that most real men frown upon wearing. Hey you metro-sexual blokes...step away at this point...I am not talking to you...drink your latte and get your pedicure. You have no business reading this forum anyhow. Additionally, experience indicates there will be a noticeable improvement in the protective characteristic of helmets over a five-year period due to advances in materials, designs, production methods and the standards. Thus, the recommendation for five-year helmet replacement is a judgment call stemming from a prudent safety philosophy.HMMM now this is very interesting...I do agree that most mfgs improve their helmets as time goes on plus with market research and field testing new styles are made and improvements over existing styles. But IMO...this is the catch 22 that we as motorcyclist are in. Is the helmet REALLY degraded to a point that it MUST be replaced or "should" it be replaced because better, faster, nicer, etc is now available? I know there is a lot of food-for-thought in this post. But these things are on my mind today...now they are on yours as well.