The other day I went skiing and on the slopes I noticed that while most skiers/snowboarders wore helmets, there were quite a few who did not.
Helmets protect some valuable real estate-namely your brain. The likelihood of suffering a serious brain injury after a crash (and by serious I mean an injury which would require urgent surgery and might leave you with permanent brain damage) is much greater without a helmet than with one.
You might say “hey, I ride safely at a sane speed and on slopes I feel comfortable with”. True enough, but others might not ride so safely. That teenage male snowboarder, full of testosterone and overconfidence, barreling down the slope right toward you, certainly represents a real hazard. And when you’re tired but decide to do that one last run, you might not be able to avoid hitting that tree in the middle of the slope.
For about the cost of a ski lift ticket, you can buy a decent helmet, even one that matches your outfit. Of course, if the helmet stays in the car, it does no good. Get in the habit of putting the helmet on as soon as you get out of the car. It just might save your brain.