From the Just Starting Out guide on the sidebar:

Should I buy/use these old skis I was given/found on Craigslist? No. You definitely can, I’d even encourage you to give a pair of straight skis a go so you can see what it was like for your forefathers. But wait until you’ve gained some level of proficiency first. The thing is, about 15 or so years ago, the concepts and principles that drive ski design underwent a fairly radical transformation. We went from essentially dead straight skis to the shaped skis you see today. The older style make learning, and skiing in general, more difficult. Because they’re straight, it takes a process of un-weighting, transferring that weight to the other ski, and then actively flexing the ski to initiate a turn. Done correctly this becomes a very precise but subtle process and is very difficult to master. Modern skis essentially turn themselves. With wide tips and tails, and a narrower waist, the physics of modern skis mean that you initiate a turn just by transferring your weight, making the whole thing a lot easier. More importantly the bindings you are likely to find mounted on them are no longer indemnified, which means they are no longer considered safe and no one will adjust or repair them for you. Like everything bindings atrophy over time. Think about it, something made up mainly of metal components that have been exposed to moisture, wind and large temperature variation and plastics that have faced the same conditions. More crucially the mechanisms of bindings are dominated by springs that obviously will lose the shape and elasticity that they require for the binding to function properly. That doesn't mean that they will fail but it does mean that they are a lot more likely to. Like skis, binding design and the mechanisms that hold and release you have been improved as well. They create less stress on parts of your body like the knees and hips than bindings from 15+ years ago. Finally, no one will work, adjust or even look at the bindings. Each binding manufacturer maintains a regularly updated list of their bindings that they continue to indemnify. This is a list of models that the manufacturer still deems to be guaranteed in acceptable working order. No ski tech (the guys in the workshop) will even look at a pair of bindings unless they are on that list. That's simply because when you blow out your knee from the binding not releasing or breaking in the middle of a run, they don't want to have lawyers chasing after then, and neither do the binding companies. It is also the case that only the bindings on that list that will have spare parts like brakes and AFDs available, so if there are issues with the bindings they will be difficult to repaired.