Every time out. I've smacked my head on the ice err..uh I mean snow quite a few times and it's saved me. Also it's warmer than a hat. If it's snowing out I don't have to deal with a wet lid. Also when I wore a hat and put my goggles up on my head they would always fog up. I don't have that problem with the goggles on top of the helmet. OH yeah and my helmet has a strap to keep my goggles from landing 20 feet down the slope when I bail.
I started out with one, but then it go too small so I haven't had one for the past 2 seasons. I will be getting one soon because I'm getting into the big stuff, along with fast freeriding through the trees.
It only took one big fall for me to realize the importance of it. I wear one all the time now.
Very true for me too. Just recently I went riding and I remember coming down a slope at a fast speed. When I tried to turn I don't know what happened but then next thing, I was on my knees with my goggles on the ground. From that moment I started feeling the symptoms of a mild concussion because I started forgetting stuff like "Why am I here?", "How did I get this board?" It was a scary experience and yet kinda funny because of all the questions my friends said I was asking but it definitely was enough to get me to purchase a helmet. Do they have ass pads?? LOL