Abstract
There are many studies on the problems of the economic life of equipment. Unfortunately, it was impossible for those papers to work out all of the problems. In this paper, we consider cases where the price rise is only based on inflation, and two cases in one of which investment brings about returns and in the other operating costs. The purpose of this study is to clarify the effect of price rise on the economic life, the conditions for the economic life to be uniquely decided in an infinite period, and the relationships between economic life and profit.
