James Turner at O'Reilly ONLamp - The Worthlessness of Code:

"When management talks about the value of code, they’re really talking about the value of the experience that the engineers gained by developing the code, as expressed in the code.

The problem is, most companies let the value walk out the door (either through layoffs or attrition), leaving them with “value” that the new engineers don’t understand, because the value is really the synergy of the code and the engineers who wrote it.

[…] We should treat code like a depreciated asset; the longer it sticks around, the less valuable it becomes. Eventually, it actually takes on negative value, because the potential security risks and support nightmares of bit rotted code can be huge. Embrace the freedom that acknowledging these facts bring, budget a periodic total rewrite into your business plans, and you’ll never end up with a piece of code that nobody has any idea what it does."