Living in sustainable economy, in my opinion is 'living in contentment'.
I am another one who lives daily by sustainable economy approach.
eg. before I buy, I carefully consider the use and the necessity of the goods.
I don't follow fashions much. I spend to live adequately but not luxuriously. I don't go for fads.
Doing so makes me understand the value of money and I learn to save more and I now have spare money for emergency.