Comment There are Laws about that, from the 1970s... (Score 4, Insightful) 323
Retaining knowledge of both software and business requirements is the 4th of Lehman's Laws of Software Development, Conservation of Familiarity.
http://en.wikipedia.org/wiki/L...
And that law is from 1978. Such knowledge isn't even as recent as the 1980s (a lesson approaching 40 years in age, I was five at the time...), it should be basic guidance at this point in time.
Anyone that doesn't realize how important knowledge of the business and operations are is one that should be ignored completely.
Advice: Always seek to learn as much as possible about the business and how it operates/interacts with the external world. This is the secret to NOT being disposable. It's also a great way to meets VP and C-Level executives.