Why it matters
One user’s extraction reduces what remains for others. Understanding both access and depletion helps explain why shared-resource institutions matter.
A worked example
Fish in an open-access fishery can be hard to protect from entry, while each catch leaves fewer fish for others and future seasons.
Illustrative example · simplified assumptionsA common mistake
Calling a scarce shared fishery a non-rival public good.
Where the idea needs care
Rules, local institutions and enforcement can manage shared resources; depletion is not inevitable.
Apply the idea
Explain this concept using a different example from your spending, work, business or a policy debate. State what stays fixed and what could change the result.
See the supporting infographic

The written explanation above is the main lesson. This image offers another way to remember it.
Sources and further study
Examples and explanations by Alibomics. Numeric illustrations are not current market quotations.
