Did you rename your dog? Was it hard to make them listen to the new name? Some owners give their dogs stupid names, hence I'm asking.
i always rename them and it's always fine
you can trick them with the old name for a while but they eventually forget
My brother did it with a 6 mo old german shepherd. Took 1 or 2 weeks for him to learn it, I'd say. Since then it's been as if he never had a different name.
Your mileage obviously could vary with an older dog/less clever breed.