Sadly, my honest answer to this is, "if I wasn't able to reinvent the wheel myself quick/well enough." It's a terrible practice, I know, but I'll usually bang away at my keyboard for a long time trying to solve a problem with core Perl or whatever module defaults came with my Strawberry Perl install (or additional modules I've already installed) before I go looking around in CPAN. :-/
Assuming I have already started looking in CPAN, I'll use any module that I can find that will, or at least seems like it will, solve my problem. As long as it at least makes some sort of sense to me when I first glance at the documentation... or that was recommended by another Monk I trust for advice.
Clever isn't the same thing as wise, but that's a moot point because I'm neither... I'm mostly just stubborn. :-)
Just another Perl hooker - My clients appreciate that I keep my code clean but my comments dirty.