For many products I think it's incorrect to say they're designed to stop working after a maximum duration. That would be a very expensive thing to actually desi

For many products I think it's incorrect to say they're designed to stop working after a maximum duration. That would be a very expensive thing to actually design and implement. You can test a component and understand its MTBF but it's much harder to design a "die after X days" without explicitly putting in way fuses that a burnt after some counter expires. Instead it's more accurate to realize things are made to survive at least a minimum period of time. Components get engineered such their MTBF is longer than some mandated warranty period. While it seems like only a semantic difference I've found thinking this way really helps me price things. If you look at an item and assume it's been engineered to have a MTBF just a bit longer than its warranty/support period you can calculate its amortized price, including an evaluation of extended warranties or service contracts. This is instead of assuming I can buy something and it will last a decade. If something lasts me longer than my estimate that's awesome and I'll likely favor that brand on my next purchase.