I would never buy a used helmet no matter how "gently" it was used. Especially since new ones are not that expensive.

As for lots of things, you can probably get a decent cheap helmet (Schwinn intercept). LIkewise you can spend over $100 and get a not-so-good helmet (eg Kask Valegro). This from a safety standpoint taken from below ratings. Fit is probably most important, as not all helmets fit all shapes of heads the same.

As good a place as any to get an idea of what's out there: https://helmet.beam.vt.edu/bicycle-helmet-ratings.html

How do you know when your helmet needs to be replaced?
After a crash or when you drop it or if it has been 3-5 years or have some other issues with it.

How long are they effective / safe (assuming no accidents)?
You should replace every 3-5 years or so.

What’s the difference between a $40, $80, and $200 helmet?
Usually better ventilation and shaping and potentially a company that uses better R+D and testing. You might also get other features like MIPS or SPIN or integrated lights or rain cover. A nicer helmet is well worth it and a CSPC or SNELL rating just means it passed the bare minimum of testing and in some cases that is it and their designs are more based on old 90s designs just without the actual R+D behind it.

Would you ever buy a “gently” used helmet?
No I would not buy a used safety device like that with unknown origins. Most people wouldn't remember if they dropped the helmet or how old it is and may not reveal they crashed in it and you may not be able to tell right off the bat.

Any recommendations on where to buy a helmet?
Your local bike shop so you can actually try it on and make sure it fits and is the right helmet.

Keep in mind a helmet is designed to protect your head and inside of that head is your brain and without a brain, no more living. Get a decent helmet and enjoy it. My Lazer Z1 helmet was expensive but it is light and comfortable on the head and really has made wearing a helmet pleasurable.

I had an older Bell helmet that was universal-sized with a wheel adjustment to tighten it. I liked it, but was looking for something a bit more sized AND being lighter in weight was a plus. I also wanted a smoother helmet without the aero points on the rear that made the helmet longer when packed in my gear bag. Even tightened down, the old Bell could move enough if it was real hot to affect how my glasses fit (and stayed put) on my head and nose. In cold it was fine. Additionally having the capability to mount a rear light was a real big plus, as my setup on the Bell was not optimal, but not a 'requirement'.

I found the multi-sized Bontrager Specter Wavecel fit really nice and did not move, and also had a wheel adjustment. However, it would not allow a helmet light, and due to the way the Wavecel material covered all the vents, I would have had to cut some of the Wavecel to fit a strap-on light. I did not want to alter the construction at all. I then tried the Bontrager Starvos Wavecel and it did not have the Wavecel material covering the 2 rear vents, and the Bontrager light strap fit very securely. It also has high marks in testing. It too fit exactly the same as the Specter, but had a clip latch instead of the magnetic latch of the Specter. Additionally, both Bontragers fit lower on the back of the head and were a bit lighter. SOLD!

One plus what the shop I bought it in had a fan setup nearby that you could stand in front of to feel the airflow. That made it easy to rule out the "commuter" type helmet I was considering. The summer heat and humidity would be too much. The ease of trying many helmets and sizes at the LBS is always my choice, but then I do not mail order shoes or jerseys.

Look up the Virginia tests and look at the prices of the top 20. You do not need to go mega dollars for top tier protection.

The miracle of Google:

https://off.road.cc/content/feature/...le-helmet-1280

Why? Does a helmet become unsafe after 3-5 years?

It's hard to tell when your helmet needs to be replaced (unless crashed). But most manufacturers recommend replacement approx every 5-6 years because of UV degradation, but it's a bit controversial and obviously depends how much direct sunlight you expose it to over those years. A better way to look at it is that technology improves over time and newer helmets are becoming both safer and lighter. So if your current helmet is 10+ years old, there are likely to be much better helmets available today.

All helmets have to meet a MINIMUM safety standard, but some helmets considerably exceed the minimum standards. They are certainly not all the same! Protection level is not necessarily in order of price, but more expensive helmets tend to be both lighter, safer, more breathable and more aero if that matters.

I would never buy a used helmet.

I bought my last helmet online, but it's important to get the right size and try it on. Ideally a trip to your local bike shop is the best starting point.

Some good info on this website:-

https://helmets.org/bikehelmetratings.htm

No, it doesn’t. No need to replace a helmet in that time span unless it has been crashed or has developed some problem.

Moreover, the safety provided by a brand new, top quality, helmet is partial and relative. Some theoretical degradation of the foam only reduces that safety by some partial and relative amount. And since no one offers any data or proposes any data-based threshold for replacement, the whole discussion is even less than theoretical. Buy a new helmet when you, crash, get the hebee-jeebies, or need a little retail therapy.

All helmet testing is debatable, including the much respected (but probably pretty good) VT testing. The "official" safety standards are similarly debatable.

I have a couple of inexpensive (~$50) Bell helmets I purchased in years past that have MIPS, are comfortable and ventilate well. I also have some expensive helmets (Kask Utopia, POC Tectal Race Spin, Bell Z20) that are the ones I actually wear. These helmets vary between $200-$300. From a pure value perspective, are they "worth" the money over the $50 helmets? I'd say no, but that never stopped me before when it comes to bike stuff. Aero carbon frames cost a ton of money and offer only highly debatable performance benefits, the same goes for carbon wheels, Dura Ace vs Ultegra etc. Similarly, the nicer helmets are better made and can be more attractive, but they're likely not really "better" functioning in any appreciable way. The Kask and the POC don't even have MIPS...

If you're only looking for functionality, just get an inexpensive, certified helmet with MIPS that fits you well and move on. I would not buy used helmets. I also don't believe that helmet's "degrade" over a few years, especially if you store them out of the sun. You probably don't want to wear a 20 year old helmet, but that's obvious.

Yes! Consider the uncertainties encountered in, for instance, drug testing on actual humans, where the mechanisms of action and toxicity are well understood and robust endpoints established!

Research on acceleration/deceleration injuries consists mainly of a few productive years from a single lab, which was shut down for abusing their primate subjects, back in the 80s.

Costco currently has a MIPS helmet in white or matte black that includes a rear light. $30. It fits the central 70% of the size spectrum. Why look any farther?

The retention system is fine, and there are plenty of vents. It's a seasonal item, so don't wait too long. They will sell out.

Ventilation design.
Weight.
Comfort features.
Adjustability.
Materials.


So besides all those very real potential differences, there are no differences.

Helmet makers and independent testing facilities suggest replacement at those times. Some could say maybe it is a tinge of marketing but it is a safety device designed to protect the most important thing your head which contains the brain. Parts of the helmet can degrade from sweat, sun damage and heat. Also if your helmet has been in a crash or has been dropped it is time to replace. A helmet is a one time use item once it has that impact it has done its job and is time to be gotten rid of.

Slightly hilarious helmet video
 

You can't say Danes don't have a sense of humor.

Who does not wear a helmet ?
 

I grew up in an era where no one wore helmets. Biked all day long as kids on BMX and no helmet. They seem to be a post-90s thing.
I ride 5 miles around the neighborhood. I can not get myself to buy a helmet. I would actually rather not ride than ruin the ride with a bulky sweaty shell strapped to my head.


I fully expect Darwin snark from this forum, but am curious if anyone else does not wear a helmet.
Please share your helmet stories!

https://www.ebay.com/itm/133729908017?

What is the deal with these $11 helmet off Ebay?
Total fake junk? Then again, foam and plastic should not be costly?

Wearing a helmet or not wearing a helmet is a personal decision. I choose to wear it but i have nothing against people who don't wear it. A helmet may be useful in mild and not so serious crashes but at the same time a helmet isn't going to prevent serious injuries and death from internal injuries caused by blunt force trauma when hit by a car or a truck.

So did I.

Grew up in Australia before compulsory helmet laws came into effect. Now I wear a helmet every single ride (it's the law).

If you buy a decent, high quality helmet, you get used to it.

Glad you had the sense to take out your TBI statement. As someone who's whole life in now jacked up due to that trust me, you don't want it!

I grew up when cars didn't have collision avoidance, air bags, antilock braking, right side mirrors, seat belts or padded dash.

Just because I survived I wouldn't want my to drive my grandchildren around in one of those cars.

If you choose not to wear a helmet then you shouldn't expect others to pay for your medical bills or after care.

I once crashed at 16mph and cracked a $250 helmet that was a week old. After regaining my wits, I was able to ride home. Best $250 I ever invested and bought the same one since it worked so well.

When I raced in events which were likely to have a sprint finish, I wore a helmet. I suffered a few crashes, tore up shorts, jerseys, and got some road rash, but never got a scratch on my helmet. Nowadays I ride for pleasure, and don't bother with a helmet.

I had a number of crashes when mountain biking and out of all those crashes only once did my head take a hit , i am glad i was earing a helmet . Even with a helmet on I still felt light headed and dizzy for a while. If i wasn't wearing a helmet i would of probably blacked out and had a concussion.