I'm a let the rider choose kinda guy when it comes to helmets. With that being said I wear a good well fitted helmet all the time.
I'm an adult, I understand the risk of motorcycles and I want to stack the deck in my favor.
I've witnessed two fatal motorcycle accidents in the last 15 years and in both cases a helmet would have(IMO) saved both lives. In both cases it was rider error, both were reentry riders on a V-twin(popular manufacturer) and they wrote checks their experience couldn't cash. In the first case one locked the rear wheel coming up to stopped traffic on a freeway and high sided landing on his skull, fracturing it. He had plenty of room to go around but panicked. He was looking cool in his 2 thousand dollars worth of leather pants and jacket but that doo rag wasn't DOT certified. I saw it from the start, I was heading the opposite direction on my bike. I got to him milliseconds after he stopped sliding, not breathing, convulsing, thready pulse and I immediately started CPR knowing he was a dead man. I did that for almost 15 minutes in 80 degree plus weather and I was wiped, CPR is quite the workout. He was pronounced on scene. I got to recover from the CPR, give a statement, wipe the blood off, and swing my leg over my bike and ride 50 miles home. I should have towed it home, my mind wasn't in the ride. I still carry that scar on my soul.
The second time I'm in a company truck, Eastbound on Bell Rd right around 55th ave(this is Vindex's neighborhood, that's why I'm pointing it out) A guy on a V-twin(uh huh) tears around me going 65 MPH plus, no helmet, shorts, T-shirt, I watch him head off to the East. He catches the light at 51st Ave I catch him, the light turns and he takes off like a bat out of hell straight pipes blatting like a loaded garbage truck heading uphill. I remember thinking what a dumbass, as he comes up to the Fry's grocery store on the Southwest corner of 43rd and Bell a car turns left from the Fry's lot onto Bell Road in front of him. The classic left turn accident, he had plenty of time even at his speed to react. He could have slowed down, he could have tapped the brakes and went right around the back of the car but he did nothing. No brake light(remember, I was behind him and I saw it at the previous light) nothing, he hit the car at 50 plus MPH and did a superman over the car landing on and shattering his face and skull and sliding another 50 plus feet. I didn't get a chance to help him, other people were there so I used the truck to block traffic and directed it around the scene. Another statement and another scar and another ride home on a bike after witnessing a fatal.
I both of these cases I had the opportunity to talk with the investigating Officer during the post accident investigation. Really opened up my eyes. Ride safe all.