This is good advice but only it has been followed from the beginning and consistently throughout the development of the original code. It is applicable to large organizations with lots of resources who hire professional developers and have a lot of people who are familiar with the code that are active in code reviews and have some minimum form of documentation / agreement on what the logic flow in the code should look like (the article does not claim otherwise). But I would implore those who work at the 80% of other companies that this advice is nearly useless and YMMV trying to follow it. The one thing that I think is universally good advice is to try and aggressively remove code whenever possible.