The Pod::Usage module provides pod2usage, which parses the POD documentation in your program and generates a usage message from it.

I have those lines in place to handle two different use cases. First, if you call this program (no, it's not a complete program, just a snippet of some production code) with a -h or --help, it will print a usage message and exit. This is standard across the code I've written at this job.

Second, there are required fields that are being checked. If there is no value for any of those fields (@services, $operation, etc.) then we present a usage message and exit. pod2usage causes the program to exit, so it's an effective check of whether continuing is actually feasible.

This implies that I keep up the POD on my programs. I consider POD necessary in production code, so that's a non-issue. Not that I've never violated that rule...

If you call pod2usage with a higher -verbose value, it prints out more information. This allows me to provide more or less detail based on how many -h flags were handed into my program. A single one means a simple usage message, multiples produce something like a manpage.