Perhaps the most dangerous side-effect of embarking on a code rewrite is that the decision condemns the old code before a viable alternative exists. Who is going to want to work on the old code with all its problems when the VP Engineering and CEO have declared the new code to be the future of the company? The old code is as good as dead the moment management introduces the word “rewrite.” As a consequence, the CEO has no fallback. If the VP Engineering’s schedule ends up taking four years instead of one year, there is no way to make incremental progress on the new features during that time.
(Full Story: Startup Suicide – Rewriting the Code « Steve Blank)