Might I suggest the book Effective Perl Programming by Hall and Schwartz?
In the intro, Hall puts it like this:
Perl baby talk is plain, direct, and verbose. It's not bad--you are allowed and encouraged to write Perl in whatever style works for you. You may reach a point at which you want to move beyond plain, direct, and verbose Perl toward something more succinct and individualistic. This book is written for people who are setting off down that path.
(emphasis in the original)
This book is all about when to do what idiosyncracies, and should help you set your levels of how much optimization makes sense. It's worth the price for the regular expression section alone.