Arbitrage between consumption and saving occurs in a context of an aging society where family solidarity is deteriorating. Maximizing inter-temporal utility makes it possible to calculate the preference for saving. The arbitrage involves subjective satisfaction with the quality of life, anticipated survival, and consumption profiles. Simultaneous equations based on the Korean Longitudinal Study on Aging, 2006–2014 (10,205 adults aged 45 and over) show that the preference for saving is determined only by and through these endogenous variables, with no other direct socioeconomic effects. People spending more money in education are those with the highest preference for saving. Socioeconomic variables influence the preference for saving in agreement to the economic theory of the life cycle, but through the structured filter of endogenous subjective variables and consumption profiles.