Nothing manufactured can be or is expected to last forever. Once we reognize this elementary fact, the possibility of a machine or building being as near to perfect for its designed lifetime as its creators may strive to be for theirs is not only a realistic goal for engineers but also a realistic expectation for consumers.Petroski nails it here, with some theological implications as well.
When engineers try to design a perfect structure, they will either cluelessly fail at their task (thinking themselves successful) or will be paralyzed by the fact that they are attempting the impossible. While it may seem counterintuitive, the closest to perfection anyone gets in design occurs when the engineer realizes that perfection is unattainable, stops trying to achieve it, and instead is free to simply try and make the design as good as it can be to meet the design requirements.
Life with God is no different. If you try to live a perfect life, you will find yourself incapable of doing so. So you will either blissfully and ignorantly fail while thinking you were achieving your goal, or you would be paralyzed with the impossibility of earning the favor of God. It is only when we admit that we are flawed inherently, that our own perfection is unattainable, that we are able to freely and simply live a life to please God.