I don't use any of the modules listed. I use Path::Class and be done with it. If I have to deal with hrefs, I use URI and be done with it. They even work together! If there's anything I need to know, it's in the POD for those two modules or there's someone I know who knows it.

In other words, unless it's something you have to know on a day-to-day basis, leave it be and know where to find the documentation. Do you really know all the different argument lists for splice()? What about vec()? I don't, but I know that http://perldoc.perl.org does. Good nuff.