I spent last winter at a Vertex VF-2 in a rented garage in Portland, machining aluminum brackets for a hardware startup that never shipped. Eighteen months later, in a code review, I realized the logic was identical.
Precision is a property of every pass, not the final one.
Tolerances compound
In a five-axis mill, a 0.002-inch deviation at the first fixture becomes a visible gap four operations later. The machinist checks every offset after every tool change. Code review, treated as in-process inspection, catches the drift before it compounds.