The Wealth of Nations by Part 2 Chapter 3 Page 35

the means by which the greater part of men propose and wish to better their condition. It is the means the most vulgar and the most obvious; and the most likely way of augmenting their fortune is to save and accumulate some part of what they acquire, either regularly and annually, or upon some extraordinary occasions.

Though the principle of expense, therefore, prevails in almost all men upon some occasions, and in some men upon almost all occasions, yet in the greater part of men, taking the whole course of their life at an average, the principle of frugality seems not only to predominate, but to predominate very greatly.

With regard to misconduct, the number of prudent and successful undertakings is everywhere much greater than that of injudicious and unsuccessful ones.