In my first few months of using Perl (back in 1995), I cannot tell you how much time I would have saved if I had known about this option on perldoc. Initially, I was learning by adapting code that someone else had written, so in the course of a day, I ran "perldoc perlfunc" repeatedly to look up the details on function calls, and I was constantly paging down to the function of interest...

UPDATE: On second thought, I have to admit that I learned a lot more about perl (and grew to appreciate it more quickly) by virtue of spending so much time with the "perlfunc" man page.