Lots of good points made for having and using GPS collars. I'll second the comments about finding your dog fast when it gets caught in a trap, and time is super critical when your dog gets catch in a snare. If that happens they can't vocalize so you won't be able to locate your dog by the sound of their barking.
Plus, I'll comment that you don't have to have a 'big running' dog to find a GPS collar useful. My Drahthaars aren't big running dogs compared to most E-setters, or Pointers or GSPs, but at times I've lost track of my Drahts on point because their dark coats bend in very well in tall thick stands of CRP or even in relatively open Mearns country. I've been standing in the bright sunshine in AZ Mearns country while one of my DDs has been solidly on point in the grasses under the dark shadows of oak trees, and I couldn't see the dog. My Garmin indicated 'dog on point' with the distance and direction, and from 40-50 yards away I just couldn't see my motionless Draht until I got closer.
