law of marginal returns or the law of increasing costs".

If you find yourself spending more time on the same material without making further progress, then it is likely that you have reached a point of diminishing returns with regards to your studies.

Sample solution

In economics, the law of marginal returns or the law of increasing costs is used to describe how additional investment in a particular activity will result in increasingly smaller returns. This means that as you invest more resources into studying a specific subject, you will eventually reach a point where additional study does not yield any further gains than what has already been achieved. You may know that you have reached this point if your studying begins to become less productive and efficient, and if it is taking longer to gain new understanding and knowledge.