>couldn't guarantee that the O-ring would perform properly. Small nit, but from a reliability perspective you can almost never guarantee something will work. I

>couldn't guarantee that the O-ring would perform properly. Small nit, but from a reliability perspective you can almost never guarantee something will work. It's a probability distribution but, to your point, you need decent data to estimate that probability. The other issue is a psychological one. Humans aren't generally wired to think about probabilities well, especially low-probability events. There's a fairly decent chance you can roll the dice over and over on these types of decisions and not have anything bad happen, leading you to think you're good when in reality you're just lucky.