Hi epl, and welcome to EpicSki. Thanks for joining us, and for asking a perfectly good--and really very important--question. (There are no "stupid noob" questions!)
Ultimately, your binding settings are up to you. It all comes down to which is more dangerous, or which risk you'd rather take--losing a ski and crashing hard as a result, or keeping your skis on and injuring your leg in a bad fall.
Certainly, the faster you go, the more dangerous both become. But losing a ski inadvertently at 40+ mph can threaten your life. Especially with today's skis and carving techniques, it is not uncommon to end up going very fast across
the hill, where throwing a shoe could find you heading straight at the trees in a hurry.
It's true that the better you get, the fewer simple falls you'll take. Especially those awkward, weirdly contorted falls that happen often to beginners and really put your knees and ankles and legs at risk, happen much less often to advanced skiers.
At the same time, of course, the opportunity for truly spectacular, high-speed crashes, however rare, increases! Personally, I'm more concerned about a ski rattling off in rough spring coral conditions at high speed, so I set my bindings well above the "recommended" DIN, as most instructors and high-level skiers do. Real race bindings often don't even go below "10" on the DIN scale.
But please do not consider this to be a recommendation!
As others have suggested, you'll know when it's time to start cranking up your DIN settings, when you start walking out of your bindings for no apparent reason. "Perfect" ski technique puts very little stress on bindings. It's often said that, if you ski well, you could leave your bindings at "1." I've known instructors who "brag" about their low settings. Until they bury their face in the snow a few times and wise up. You simply can't ski at a high-performance level, regardless of your skill, without getting knocked around and needing those bindings to hold you in now and then. (And if anyone thinks you do, you need to ski faster!)
Today's bindings are very good. Compared with older models, they absorb the quick, harsh shocks that don't usually hurt us, and release easily when they need to. They don't have to be set as high as before just to stay on. So even "high" settings are actually quite low compared with a couple decades ago. I usually set my bindings at 10 or 11, and I'm always amazed at how easily they release when they need to--I never even notice the force. (That's 3 or 4 numbers above my "Type III" recommended setting--high by some standards, conservative for many.) They rarely come off when they shouldn't. And when they're rattling around on the hard, rough, frozen conditions of an early morning in spring, or slicing at speed through a tight glade, or holding a tight line in a race course, it's comforting to know that my skis aren't going to just fall off!Again, please, do not take my words as a recommendation for setting your own bindings.
There are risks both with too high and too low, and you must make your own decisions as you weigh these risks yourself. If I had to "officially" recommend, I'd suggest keeping your bindings at at the recommended DIN for whatever type of skier you think you are, at least until you find yourself coming out a few times when you know that you shouldn't have. Trust me--you'll know!
I'll leave you with a photograph from the Noram Giant Slalom race at Keystone last fall. I suspect that this skier would have had some choice words for his ski tech or binding manufacturer at this particular moment: