This paper attempts to derive several economic conservation laws and to test the validity of the optimal growth models using the income/wealth ratios for the United States, Japan, and other OECD countries. Conservation laws vary with the type of the objective function depicted, such as the maximization of the aggregate consumption or the maximization of per-capita consumption. The operational concept of “wealth-like quantity” is identified, although the Goldsmith-Kendrick standard definition of “net national wealth” should not always be used. The last section of the paper takes up an empirical analysis to determine how different economies have achieved long-term (optimal) growth. The U.S. economy has been operating rather efficiently, whereas the Japanese economy, after the oil shocks of the 1970's, has behaved differently, leading into the bubble period of the early 1990's.