Well, I'm only on the long long way of trying to become a perl veteran, but here are my 2 cent

In my opinion you need a bit of both. You need at least one big mess of program you have to change to find out why to do proper programming and what not to do, and a good perl programmer to explain some problems that are not so obvious (you can tell a kid twenty times that fire is hot; but this is not so effective as if it feals the heat, since then it will know it forever)

On the other hand you need good code to find out some possibilities how you can do something, and improve your way of coding.

And very important is to have to change code you wrote some months/years ago