As a teacher it can be helpful to consider Āsana as
vehicles to transmit the fundamental principles of practice.
For example a cardinal principle of practice is that Āsana
have a primary and a secondary aspect within their Lakṣana.
Thus we must inquire into what is the primary aspect in this Āsana,
and what is the secondary aspect in this particular Āsana?
The idea is to maintain the integrity of the primary characteristics.
Thus we may need to compromise the secondary characteristics.
For example in Uttānāsana to sustain the primary work in the spine
we can consider a secondary compromise by releasing the knees.