Quote Originally Posted by Aspenor View Post
Casting barkskin on casters, clerics, barbarians, some fighters and rogues, and some rangers, and many bards is a COMPLETE waste of spell points.

Maybe you should ask yourself whether you really need barkskin or not, because more than likely you do not. If you have less than 50 AC, the ranger should not bother.
Of course that's 55 on hard and 60 on elite.