Required Reading for everyone who said "If it ain't broke, don't fix it."

http://pythonsweetness.tumblr.com/post/64740079543/how-to-lose-172-222-a-second-for-45-minutes

Here an important lesson.

Code Rot is Real.  It Leads to Subtle and Expensive Bugs.

Claiming that code cleanup is just pointless "gold plating" is the kind of thing that can drive a company out of business.