All I can say is that if there is plenty of clay I can turn it into pots. It seems like such a simple factor in one's production. Having just pugged the clay, I pulled off a pile of pugs, versus opening a bunch of plastic bags. I can't tell you the difference in mixing your own clay versus commercial clay. It's not for everyone and it probably doesn't compare if you add up time, equipment needed, etc. But it makes me excited to make pots and that is probably the single most important factor in any good work! But how do we quantify that?