That's an excellent point, and one that I think a lot of people forget.

I've just been accepted as a Ph.D. student. (Yay me. :-/) So I've had the opportuntiy of applying to teach undergrads, particularly first-year CS classes. I don't like that idea. To my mind, it's hard to teach a class when you don't know what's hard and what isn't. I've (probably) already forgotten that --- I'd rather teach a fourth-year complexity course than a first-year intro-programming course, because I can remember what's hard about complexity --- but I can't remember what's hard about learning to program; I need to re-learn all that.

I would wholeheartedly welcome a "Perl for newbies by newbies" tutorial --- or a regular column. I've already forgotten what's difficult about using Perl's filehandles and regexes (Edit: Yeah, as if that's all), and that makes it more difficult for me to figure out what bits need more detail when I'm writing for someone who hasn't.