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Old 06-07-2017, 07:05 AM
LSLGuy LSLGuy is offline
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Join Date: Sep 2003
Location: Southeast Florida USA
Posts: 19,622
There's a joking saying in racing that the ideal racecar disassociates into a cloud of dust a couple feet past the finish line. Any greater durability is wasted weight you can't afford.

Seriously, Mangetout nailed it.

If you want 99.999% probability of a complex device lasting X years under Y assumed conditions, then (assuming Y turns out to have been valid assumptions) the thing will eventually fail when the first component gets down to (roughly) 50% probability.

Which will be long after that same component passed through the <99.999% probability threshold on the way to its eventual failure.

Last edited by LSLGuy; 06-07-2017 at 07:09 AM.