This I guess is a corrolary to if it ain't broke then don't fix it.

I would consider any code that's too complex to be understood without comments to be broken :-)

If you don't spend the time to make your code simpler it just gets more and more complex over time - until you eventually end up with a big ball of mud.

Don't accept the evils of code entropy! Continually refactor your code to make it as simple as possible. You'll be surprised how quickly it pays off.