Modern engineers: we need to make sure it breaks at approximately 36 months to ensure low ability to claim warranty while also ensuring the customer believes it could have been a fluke.
Or, roughly translated into engineer speak…”anyone can build an aqueduct, it takes skill to build an aqueduct using the minimum amount of material required”.
It depends on the way you think about it. When designing, I want all my parts (other than user replaceable wear components) to fail at the same time. That means nothing is the weakest link, failing earlier than the design otherwise could handle.
Anyone can design a 70 mile long aqueduct. It takes a skilled engineer to design a 70 mile long aqueduct using the minimal amount of materials necessary.