Functions: how long is too long?
Groxx: A general rule I hear is screen +~50%.  Once you go beyond that, a study I read a while ago (apologies, no links) showed a huge leap in error, they believed stemmed from our difficulty remembering complex / random things.  With my own testing, I'd say it fits pretty close.  On-screen is pretty limiting, but 2x screen gets harder to be certain about everything in it, all the time.  My error ratio is definitely best when I keep my functions below 2x screen height.That, and once you get into the hundred+ lines of code, you are probably doing something that's more easily summed up as a couple pieces.  Using multiple pieces also has the advantage of it being very easy to rapidly change / experiment with your code.