Economists typically measure the consumption of a good through:
the amount of a good that is actually used rather than bought.
This approach focuses on the actual usage of the good rather than just the quantity purchased, as it provides a clearer picture of consumption behavior and its economic implications. However, in many contexts, economists may also look at the amount of a good that is bought, as purchasing data can serve as a proxy for consumption. Ultimately, the specific method can vary depending on the context and the goals of the analysis.