>> the company that's going to put you out of business won't have any legacy code. Even assuming their newly-minted code is better (which others have disputed)

>> the company that's going to put you out of business won't have any legacy code. Even assuming their newly-minted code is better (which others have disputed), what they don't have is loyal customers and brand recognition. If you're worth competing with, you do. >> I think you need to have a really good excuse not to completely rebuild your product from scratch every now and again. There could be many reasons. 1) That's expensive. 2) May introduce new bugs. 3) Interface changes may alienate existing customers. 4) Switching technologies may require new developers. I wouldn't say "plan to rebuild from scratch periodically." I'd say "design your software to be flexible, watch your competitors, and iterate to ensure they don't leave you in the dust." If it becomes clear that you can't compete on features without a rewrite, then consider it.