I agree that code all is disposable, old and new alike. But without knowledge and insight you won't know which code to throw away. So you either end up being t

I agree that code all is disposable, old and new alike. But without knowledge and insight you won't know which code to throw away. So you either end up being the guy who introduces the new product that everybody complains about because it doesn't do what the old one did. Or you end up having to maintain both old and new because not everyone will switch to your new codebase.