I like to think of a leash as a means to prevent the dog from running into the road or running away if a recall has not been fully trained.
Too often we rely on the leash and not on verbal cues or a trained behaviour of "follow me" when walking the dog. We pull them when we want to move on, change direction, avoid a puddle not jump on oncoming people and so much more.
I want my dogs to learn - hang around me for potential rewards (tug, chase toy or food) voluntarily vs go away from me because I can't physically restrain him via the leash.
This begins when the dog is a puppy. Reinforcing whenever he happens to be in the "drop zone" as well as being creative and mindful when I need to get him to move **without using the leash, even when it's on**. Hand claps and kissy sounds are two easy ways to do this.
Even though my dogs are fully grown, I am still mindful of giving them the opportunity to move along when asked vs using the leash to move them.
There are times I do use steady pressure on the leash to get them moving, but only after being given the opportunity to respond to my cue first.