That will never happen. It would take the <i>simultaneous</i> failure of two independent systems, each of which are highly reliable. If the MTBF (mean time between failures) of one component were, let&#x27;s say, ten years of continuous use then they each have a 1&#x2F;87600 chance of failing in each usage-hour.<p>The odds of a simultaneous (within one hour) double failure is the square of that, or 1&#x2F;763760000 per hour. This corresponds to a MTBF of roughly 3836880000 hours or 438000 years.