I feel confident in my ranging abilities out to 40 yards. In RJs example I couldn't imagine someone guessing a 9 yard difference at 24 yards but I guess it could happen. I usually hunt from the ground and feel it is easier to range distance from the ground than in the tree. Last years deer was at 36 yards and I guessed 35 before I shot.

My 30 to 40 yard pin is not very far apart so I held in the middle of the two and sent the arrow to watch it hit perfectly. Then I watched the deer fall over in sight.

If I had a range finder it would just be another thing I had to carry and I like to keep my pack light and small. I really don't see the need for one for myself.