[a2decrow]

The first thing that came to mind:

Eagleson's Law: Any code of your own that you haven't looked at for six or more months, might as well have been written by someone else. (Eagleson is an optimist, the real number is more like three weeks.)

Writing documentation isn't so much a "how" problem, but a "why" problem. Most people writing code in their own time can't be bothered also writing documentation for it.

Writing code is fun (mostly). Writing documentation is not.

[finnh]

Wow, I don't agree with that "law" at all. A couple times in my career I've worked for 5+ years in a codebase that I started, and it's always easier to read my old code than to read someone else's. Like, waay easier (unless the other person's code is super duper clean).

[CM30]

Those two views aren't necessarily opposites. Your old code can be hard to read, and other people's code can simply be even more difficult to understand than that.

[openmosix]

"When I Wrote It, Only God and I Knew the Meaning; Now God Alone Knows"

[qbrass]

Not even God knows what that regex does.