While there is some amount of uncertainty in the length of our lifetime, we have the means of influencing it with various choices, such with different diets, occupations, investment in prevention and physical activities. But as these choices all have a cost, whether monetary or in utility, people face trade-offs and there is something of an optimal age. How should we think about it?
Carl-Johan Dalgaard and Holger Strulik make a first attempt at answering this question by positing an "aging law of motion" that defines how a human body become more frail over time and how this can be influenced by various costly choices. They use some recent insights from medicine and biology on the speed of aging and build a model that is able to replicate the impact of medical progress on life expectancy, or the relationship between labor productivity and life expectancy, or cross-country differences in life expectancy. This is all exciting stuff, but I am puzzled that individuals have only utility from consumption. One would expect that the value of life goes beyond just consumption, and empirical studies confirm this. This is not important when the lifetime is fixed, but when someone can influence it, it becomes critical. I am looking forward to a revision of this paper.