User blog comment:DE-Note/What Determines the Strength of One's Aura?/@comment-7622429-20150529163833/@comment-25555436-20150529181519

In ultra-simple terms, what Perphaps meant was that you may have lots of small shields made of rock (high quantity), but they won't last long (low quality), while one may have only few shields (low quantity), but each one is bigger and, being made of refined diamond and steel, lasts much longer (high quality).

And the Aura's quality would be determined by the training and focus one puts into it.