True, but if he decides it should last the 30 year it's a must. And based on the assumptions he made in the first post I think that's the case. But that is something completely different then you said in reply #7. That's just extending the spec to, yeahh, after 100k cycles the change is still small so you could say it's not "one in a million chance that 1000 people will die" but it's probably "one in ten million chance that 1000 people will die" and that might be fine.