"It's not so much that you need to understand every in and out of the field. What you need to understand is effort level required develop something[1], and when

"It's not so much that you need to understand every in and out of the field. What you need to understand is effort level required develop something[1], and when you're clearly getting BSed." Those are not trivial things to do. Is not so rare for me to underestimate the effort required for a change in own code (but this might be because I'm not such a great programmer).