We're taught to take it as far as is needed. Typically, after an attacker has his energies redirected (see video
), he understands the necessity to rethink his motives. Should the attacker decide to pursue the matter further, it then becomes necessary to to belabor the point, i.e. bring a little more pain and, if necessary, debilitate the attacker.
I favor joint locks and throws because they require far less energy on my part than, say, punching or kicking (although we learn plenty of that as well).
My aikido instructor always used the analogy of a chair to help illustrate the point; when a chair is sitting on all four legs, you have to use more energy to move it than if it were propped up on just two of it's legs. Now imagine the chair tilted back on only one leg; your ability to move the chair in any direction you choose requires little more than a thought and a gentle push. It's the same way with joint locks and torques. Owing to the fact that we naturally and reflexively move away from pain, the attacker essentially helps me move him where I need him to move.