In fact you probably shouldn't use exit 0 for an error at all. Better to use die $message instead.

Giving a non-zero exit code (as die() does) on error makes combining scripts in shell scripts / one-liners a lot easier:

my-shell$ check-this-config-file.pl && then-stop-this-server && then-d
+o-a-lot-of-stuff.pl && then-start-that-server
[download]

And yes I do this a lot.