* Documentation is essential if multiple programmers are going to touch something, which will be the case in the vast majority of projects.*
I don't know. (a) This is Lisp, we need one tenth the programmers of other languages meaning it is one tenth likely anyone will ever look at my code. (b) Even in tall buildings on projects with twenty people when I was on a trekking vacation in the Andes and my program broke, guess whose yak-phone rang?