With all his wheezing, snorting, and coughing on a normal basis, North can't handle the additional pressure of walking while wearing a collar. I only buy harnesses and strongly recommend them for both training purposes and for safety, security, and comfort. A harness distributes the weight around a dog's body as he pulls, preventing the choking effect that collars can have on the more vigorous tuggers – they're actually at risk of neck and trachea injuries while simply having fun! Add to that, there's no worry that my precious pet will slip out of my hands or out of his harness as we spot birds and squirrels on daily walks –
and that's all the more reason for his extensive collection!