For just validating that everything is working the way it's supposed to, I normally prefer the use of printf and Data::Dumper (and CGI::Carp for web-based apps).

Once I've identified that there is a problem (though not necessarily what the problem is), that's when I use the debugger. If you're not dealing with a specific issue, or indeed aren't aware of any issues, then trodding through the debugger can be arduous, especially if you use a lot of subroutines.

And, of course, debugging someone else's code...There's nothing wrong with having subroutines 10 deep in the call stack, until you try to step through them all :o