I used one for a couple seasons, but thru practice can judge within a couple yards without one. I practiced from my deck and moved the target around in the back yard w/o knowing the distance. This doesn't work too well anymore as there's not a spot in the yard that I don't know the exact distance anymore, but it translated into the woods. Another way is to pick out an object as you're walking (anywhere) and try to judge the distance. Then just count your steps. I would pick out a car in the parking lot at work on the way in and out.