For years I didn’t have a rangefinder, instead relying on rocks, sticks, and even bits of tissue paper as distance markers. Now, without moving from my perch, I can determine the exact distance to almost anything within range.
When bowhunting, I can determine my aiming point regardless of the height in the tree because my rangefinder allows me to easily verify it. Most laser rangefinders are true to within a meter or yard. Leupold’s RX-Full Draw has a range of 600 to 800 yards and features recent signal processing techniques that promise accuracy to within a half-yard.