Working with directories in OS X

A philosophy question...

For no particular reason, I keep my Perl scripts in user space
(/Users/grant/bin/perl). The scripts work with directories elsewhere in my
user space. These scripts get deployed to other machines and are run by
different users.

Is there a good way to tell Perl about the user space? Or is it
easier/better just to use the system space?

Regards,
Tim Grant
-----------------
Here's an example of the mess I've made for myself:

#!/opt/perl/bin/perl -w

use lib qw(../../lib); # ~/bin/perl/lib
use HOMEMADE_MODULE;
# Relative path breaks if script moved/run from another directory


my $path = \qq"/users/grant/data/vendor1";
 # Absolute path needs to be changed if script moved to different computer