I always try to use quality parts. That is a best practice that I got used to years ago. But let's say that I only install the very best, with the lowest failure rate and the highest ratings. It might still fail. Do you write in a clause to your contracts? Maybe a mason jar that you put your change in each night with a label that says "in case of failure, break glass, visit Coin-Star?"
Plus, I have never had a problem with this valve in the past, have put in about 30 more since then, and plan to continue using it in the future.