by Engineer Spike
Quiet Guy was talking about cyclical loadings. When I was in engineering school, we had a lab where we tested the limits of certain grades of steel under cyclical loads. Under a certain loading, the material would last forever. The higher the load (above the infinite load limit), under the cyclical loading cycle, the shorter it would last. When GE (or Maytag, etc.) designs a washing machine, they look at the average number of people in a household. They then calculate the amount of laundry that this average family generates. This way they can design the machine to fail just after the warranty expires, and they will buy a new one, or spend money on parts.