in reply to When to use modules?

I don't think this is a good example. I can't imagine that your script uses cookies without any form decoding, page formatting or interaction with a file or database of some sort. You do all these things by hand too? The cookie function does a lot of things you neglect in your simple print statement, like entity encoding and expiry date processing. Also, your statement is short, but also plain wrong (no doublequote escaping).

now, i know, that perl-programmers love short code. The less writing, the better.
I can only speak for myself, but I suspect that lots of other Perl programmers agree with my if I say that the quote above is false. I like clear code. In Perl, that often goes hand in hand with short code because of the expressiveness of the language. I like Perl "golfing", but not in production code where I (and the team I work with) have to maintain it. There, I strive to create solid, clear, maintainable code.

Most of the time, modules take a lot of work out of your hands and let you concentrate on the problem you're trying to solve. I probably could write a database interface or XML parser if I wanted to, but very capable people already have done so, excellently I think, and let me focus on the problems I have to deal with.

Arjen