I know how important it is to you to be able to give your dog(s) off leash freedom. And as a trainer, I want nothing more than to help you teach them to listen reliably when they are off leash.
You have to remember that your dog doesn't come hard-wired with an understanding of how to live safely in this world. He doesn't know cars could kill him and that he should look both ways before crossing the road. He doesn't understand the concept of property lines and boundaries and that wandering out of your unfenced yard is a faux pas and could potentially cause conflict with your neighbours.
All he knows is there is something really interesting over there and he sees no reason why he shouldn't go check it out. And because he's off leash, there's nothing stopping him from doing that.
What he needs from you as you help him learn those important boundaries is safe management. Quite simply that means that while you are in the process of teaching him to come reliably when called and to otherwise stay in close proximity to you, you keep him on a leash, long line, tether or simply put him away if you can't keep a close eye on him.
If you don't, continuing to let him run free and uselessly calling him when he doesn't or won't listen will allow him to rehearse and solidify the behaviours you don't like - such as ignoring you, running away, chasing after people or other animals and not coming when called.
It could even get him killed.
The bottom line is don't give your dog more responsibility than he is ready to handle right now or more than he actually knows how to handle.
Off leash freedom is earned, it's not a right. So unless your dog is in a safely fenced area, keep him on leash until he can prove to you that he's capable of handling more.
His life truly depends on it.
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