I too, used to back of bindings in the spring, then readjust in the fall, but I stopped doing it a while back. In all my years of skiing and hundreds of skis that have seen very hard use racing and training I've had two binding failures, both of them were plastic housing that broke when I went to put the skis on for the 1st time of the season. A pre-season test might have caught it, not sure if the cold exacerbated the failure. Both were from the same family, ESS VAR that the heel cup snapped, and then a pair of Atomic bindings where both heel pieces had an internal plastic cam break. The ESS VAR were old enough that I just pitched the whole ski/binding, but the Atomics were ~only 2 season old. I contacted the place I bought them from and it seems there was a recall on the bindings as they replaced the entire set for me and they wanted the broken bindings sent back..
Thankfully both failures were at the base of the hill, rather than on the trail. I've broken far more skis than bindings, at one point Atomic was making SL skis out of the most fragile ceramic they could find, I was going about 3-5 days max on them before they'd delaminate. The factory was, however, fabulous about replacing them!