I use Montana Xtreme Bore Conditioner on a few of my rifles. I did this to see if it really makes a difference. Well it does. It makes them load easier and clean easier. Not much mind you, because all my rifles are in good shape. But my Remington Genesis especially was a good case. I would have swore that bore was clean. I used the bore conditioner and could not believe the gray what ever it is, that came out of the thing. Now it looks like a mirror down there. It loads like a dream, accuracy is excellent and clean up seems also easy. Although I never complain about the cleaning part. That is all in the sport.
If your rifle shoots well, loads well, and you care for the barrel, a bore conditioner is not necessary. It is just a little more protection some of us are adding. I like to do it to my more expensive rifles, just to make sure they stay in pristine shape.