When you are stationary it is pretty easy to check the wind and you can use a natural checker like leaves,tall grass etc. or your feather tied on the string. When you are elk hunting trying to follow a fast walking herd on very dry or sough wet ground you need something really consistent,and something that you can use several time because in the elk woods the winds swirl pretty much.This is a case you can need some good powdered wind checker.A couple of bottles can last a season.