Startup suicide -- rewriting the code

This is a good article on the same topic:

http://www.joelonsoftware.com/articles/fog0000000069.html

While there are certainly valid points (re-writes take a long time, one might forget to add features to the existing code while working on the new code), it is sometimes necessary nevertheless.

Mozilla was a re-write of Netscape 4.6. Can you imagine if they hadn't done that? Would anyone still be using Netscape today?

When Steve Jobs was brought back on board to Apple they decided to create a new operating system rather than continue with their legacy Mac OS. OK it wasn't a complete re-write (they had NEXTSTEP) but it still took years before Mac OS X was released; many parts are indeed new. Can you imagine what would have happened had they not taken that decision? Linux, Windows 7 64-bit, and Mac OS 9?