Iyengar Yoga does not aim at the perfect posture - but aims at bringing the performer to the full use of his potential, even when that leaves the pose imperfect. External tools, aids and props tend to distract the attention from the real pose and give a false sense of accomplishment. It is better to do the pose slowly and to your capacity even if that capacity is limited, rather that force the body with the aids of props to do what its own innate intelligence is not yet capable of handling.

So a healthy body that still does not achieve perfection in a pose must not be given a prop just for the sake of helping him to reach perfection. We as students and teachers must work on the flow of energy and inner awareness, persistence and much repetition - and eventually greater perfection will be achieved. But never should we curtail the learning curve by allowing unnecessary use of props.