A rational decision maker compares the expected marginal cost to the expected marginal benefit of any activity.

Expected Marginal Cost

The anticipated cost of producing one additional unit of a good or service, taking into account all relevant factors and future circumstances.

Expected Marginal Benefit

is the anticipated additional benefit or utility obtained from consuming one more unit of a good or service.

Rational Decision Maker

An individual or entity that makes decisions by systematically considering the available information, alternatives, and potential outcomes.