Why do spinning reels have these? I always leave mine on and can't think of a  normal situation where it would be beneficial to turn off the anti reverse, but it must serve some purpose or else they wouldn't have them. So when and why should you turn off your anti reverse when using a spinning reel?

To properly fight a big fish on light line, the drag cannot the trusted to operate smoothly, so the anti-reverse is turned off and the handle is turned backwards to absorb the fish's pull. It's call backreeling.

It's a technique you should practice just in case.

I am always intimidated to attempt back reeling.  I have read all sorts of articles on this.  Some of them say that its pointless to back reel now because modern drags are miles ahead of what they used to but I have also read several accounts of how back reeling is still very beneficial.  I would like to try it sometime but I would rather not try it on a big bass.

I know that some people, including my partner, prefer to backreel. Personally, I never had the desire to learn it and give it a try because I have never lost a fish that I can recall that I could attribute to faulty drag.

I learned to back-reel when ice fishing and while I hardly ever do it when bass fishing, I think it is a skill that should be learned.  

If you find yourself fishing with 4 IB fluro and catching giant Smallies then you may want to back-reel.  Once you get the hang of it, its a lot of fun also.

No way for me.

I rely on a very good drag system that responds instantaneously

and performs flawlessly. I could never duplicate the intricacies

when the huge brown fish surge.

8-)

No way for me.

I rely on a very good drag system that responds instantaneously

and performs flawlessly.

8-)

X2

rw -  thats because you (like i) use a shimano and we dont have to !