It is easy to be frugal, but difficult to be frugal. Sima Guang stressed that we should consciously keep frugality and prevent extravagance and waste, and advised future generations that the famous saying is "from frugality to luxury, from luxury to frugality". This sentence comes from Sima Guang's "Training frugality to show health", which means that it is easy to go from frugality to luxury, and it is difficult to go from luxury to thrift. This sentence expresses Sima Guang's vigilance against extravagance and waste and his admiration for the virtue of thrift, and warns people to keep frugal living habits and prevent them from falling into the quagmire of luxury.