How to Avoid One of the Costliest Mistakes in Software Engineering

A complete rewrite is never a good idea. While this article gives a good behind the scene look at what (could have) happened with Google Docs, it doesn’t really go into the details as to why rewrites from scratch don’t work. While almost 15 years old, my reference on the subject remains Joel’s excellent “Things You Should Never Do”. A must read.

My favorite quote from that article:

When you throw away code and start from scratch, you are throwing away all that knowledge. All those collected bug fixes. Years of programming work.