I am probably in the minority here, but I never felt like a rangefinder was necessary, unless you are taking shots over 35 yards and the arrow starts dropping more. I have one pin to keep it simple. The only distance I have to estimate is 25 yards. I hold dead on from 5 to 25 yards weather I'm in a tree or on the ground and it will be a kill shot. If the deer is 25 to 35 yards, I just hold a little high. OK, I need to know approximately 35 yards, too, and thats my limit.
Like Southern Man, I realize that there is a differnce in an 18 yard shot compaired to a 24 yard shot, but come on, not much. Unless your trying to sneak it through a 2" opening (who would? ) then it doesn't matter.
I know that a lot of guys can shoot accurately beyond 40 yards, but I'm not one of them. I just feel there are a lot more things to go wrong on the longer shots (besides my accuracy) like wind, more reaction time for the deer, unseen twigs.