[lmilcin]

It should read "communication". The hardest think about engineering is communication.

Requirements is a communication problem.

You can help your engineering by making sure ideas are correctly named, that definitions stay true to principles and the same throughout the company.

When software is built on immutable principles then it hardly ever needs to change because principles do not change (or they are not principles).

I have worked developing various banking systems. Most of the time it is not requirements that change, it is people discovering they have different definition of something that other people have and the change is to accommodate differences in understanding.