I am not going to start preaching as to weather people (pros or not) should wear helmets or not.   God knows I've had enough people try to preach their opinions to me, and there is nothing more annoying.     I am simply going to let you guys know what I have done, and what I am choosing to do.
In the beginning I did not where a helmet, only racers wore helmets, and the topic wasn't really there.   In 2000 I believe I was a year or two into park skiing and I decided I should wear a helmet.   I was 15 years old and I decided to get a helmet, my parents didn't say anything to me as to weather they thought I should wear one or not, it was a completely independent decision.  That lasted about a year and a half, at which time I said "fuck the helmet" and stopped wearing one.    I always kept a helmet around because you are forced to wear one when competing, but I did not wear one on my own time...  ever.    This has been going on ever since.   In fact, that past 5 years the helmet I have used for competition has been a skateboarding helmet without a proper chin strap, so it was essentially completely useless as a helmet.
Now, two winters ago I was demoing some rockered skis (K2 Pontoons) and was going to hit this pillow line cautiously, controlling my speed as I went down, but due to the min edge control of the Pontoons, controlling my speed was an impossibility and once I got onto the line, I realized I had no choice but to point it... which I did, but when I tried to dump my speed at the bottom my skis washed out from under me and I was then going at speed, head first towards ever tightening trees.   I scratched at the snow and managed to get myself sideways quick enough so that when the inevitable happened (hitting a tree) I wrapped around it on my side, bruising my ribs and stuff, but my head didn't hit a tree.    It was an extremely close call, and it should have been a wake up call...   but I went down to the base, drank a beer and got over it.    That was two years ago.
In march this year i started having anxiety issues.   Now, I personally linked them to pot, but blood sugar levels could be a factor.    Shit like eating a whole box of nerds in one sitting (while sitting around smoking bongs watching movies), or what is probably the main  cause of the anxiety is Happy Planet.   When I am hungover, or just feel like I'm ballin' I'll buy some Happy Planet and pretty much chug a full 2L of juice.   Without the pulp still in the juice it's hard for the body to digest it properly and your body gets a sugar high of crazy levels...   Now, I'm not entirely sure if this is the direct cause of the anxiety, but a friend of mine used to suffer from anxiety and this was the cause...   almost fast tracking himself into diabeties, and the anxiety was an early warning system of the body/brain.    So, this has nothing to do with skiing or head injuries, but with drug use, anxiety issues and previous concussions, I am starting to realize that the brain is a very fickle thing, and if you mess your brain up, there is no reversing the damage done.     Because of this, I am going to buy a proper helmet and use it every day.  I like who I am, and I don't want change (physical or mental) forced upon me from outside forces.