That's true, although it raises a question: is the maximum you're willing to spend a trait of your bill of materials (I'd argue no), or of some other thing, for

That's true, although it raises a question: is the maximum you're willing to spend a trait of your bill of materials (I'd argue no), or of some other thing, for example your overall project. In that case you could have a method that validates your BOM against your project requirements.