Formal equilibrium requirement: signal construction rate ≥ entropy rate × environment factor. Sₑ ≥ Eₑ(γ). Operationalized: quarterly schema updates + corroboration campaigns must exceed decay rate. Higher γ (faster-changing environment) requires higher maintenance rate. Use for: maintenance budgeting (faster environments need more investment), posture forecasting (predict forfeiture from maintenance gaps), strategic planning (account for environment acceleration). Explains why static infrastructure fails — entropy compounds, maintenance must compound faster. Foundation of entity engineering methodology.