Hey guys, I was curious what kind of collar would you use on a 16 week old puppy? I haven't been putting a collar on him and only harnessing him when we got out. He gets freedom from the harness when we are inside. I watched leerburg and they didn't recommend collars until the dog is older and for training purposes. Please let me know what you guys think is the best collar and should I always keep it on? or just daytime and take it off when he sleeps through the night?