We smooth our lifetime expenditure because we lack the ability to manage and store our purchased goods and services.

We want to smooth our lifetime expenditure; however, we do not care about smooth our income. Why does this happen? Although future incomes and prices are all uncertain, we are more confident about our ability of managing our wealth instead of  goods and services consumed. When we receive our incomes, we feel our wealth is increased, and wealth can be managed well and used wisely. However, when we consume goods and services, because they have various characters, it costs much more to manage and store the goods and services after we consume them. Therefore, in order to reduce the costs and use our money efficiently, we tend to consume goods and services when we just need them. Moreover, we want our life standards to be constant; therefore, we tend to smooth our expenditure across our lifetime. To conclude, We smooth our lifetime expenditure because we lack the ability to manage and store our purchased goods and services; otherwise, we might spend all at once.