Why do many countries conduct a population census only every five or ten years?

Countries conduct a population census only every five or ten years primarily because these operations are extremely expensive and logistically demanding to execute.1

Because a full enumeration of every person in a country is a massive undertaking, it is not feasible to perform them annually. In the years between these formal counts, governments estimate population changes by utilizing vital statistics—such as birth, death, and migration records—to track growth or decline from the last census baseline.1

While the interval is often decennial, such as the constitutionally mandated U.S. census, some nations choose a five-year cycle or irregular intervals depending on their specific administrative needs and resources. These periodic snapshots remain the fundamental basis for demographic research, providing the essential data required for government planning, the distribution of public funds, and the determination of political representation.1234