I've been riding for fifty years last month, and coaching kid-learn-to-ski-racing for about thirty. Two years ago, I took a very hard hit from a large adult out of control on the ski area. Helmet? you bet! I was VERY lucky, had bilateral hematomas, and have just finished a couple years of multiple surgeries. the top two thirds of my skull is now titanium mesh. I've worn a helmet for more than twenty five years, ever since my kids had to wear them to ski race. Sometimes luck is good, sometimes bad.