My father was a brilliant chemical and mechanical engineer. When he bought a new 1964 Pontiac GTO, he was so curious about the engine that he took it apart and laid the pieces out on the garage floor. And when he put it back together, he didn't have any parts left over (a skill I never mastered...).
But one thing Dad always talked about was the primary operating philosophy of the Shade Tree Mechanic: "If it ain't broke, don't fix it." And for all of his life, and for most of mine, that philosophy has worked.