A commons is a shared resource whose use and management matter to a group. In a tragedy-of-the-commons pattern, individual use creates costs or depletion that the arrangement fails to contain. One group reserving unused slots can reduce bookable time for everyone else.

Define the resource and its limits before naming the pattern. Shared resources differ: a room’s available hours are not interchangeable with a renewable fish population or people’s knowledge. Record how use changes availability and how it can be restored.

Depletion is not inevitable. Rules, monitoring, participation and ways to resolve disagreement can help, but their effectiveness depends on the resource and setting. A rule on paper is not proof that the resource is well managed.