Depletion indicators can carry similar units while built to inform distinct questions. Reserve- life ratios, trend-persistence metrics, and gross-removal pressure scales are widely interpreted as a literal “time to depletion,” despite measuring distinct physical or statistical quantities. Compounding this ambiguity, compensatory scalar aggregation routinely masks critical physical deficits behind positive aggregates. In this paper, we resolve these confusions by constructing a typed stock–flow accounting ledger. By tracking conserved substance classes (moieties) independently, conservation laws remain typed: under the declared type discipline, biomass, financial flows, and biodiversity metrics do not form one typed scalar conservation readout. A cross-type numerical sum may still be computed, but it is an additional declared readout—not a conservation law of the typed ledger. Mass conservation follows directly from the incidence structure of the compartment–flux network, nonnegativity is guaranteed by donor limitation (primitive outflows vanish whenever their source compartment empties), and ecosystem services are treated strictly as observable readouts rather than conserved mass. We formalize three certification layers: an exact flux-identifiability criterion for what an observed readout trajectory can and cannot determine about unobserved primitive fluxes, the conservation-law projection of an already balanced trajectory, and an envelope theorem providing verifiable flux-bounding certificates. The closure calculus is state- and boundary- conditioned, and it separates material not yet returned by a declared use deadline from ma- terial never returned: the first is a recoverable in-transit or pipeline requirement, while only the second liquidates the available-plus-recoverable stock. For the closed finite-donor ledger, we establish the natural-block mass identity, orthant invariance, the absence of interior rest points under positive extraction effort, a characterization of the vanishing-extraction rest set (extinction, carrying capacity, and a frozen-biomass face), and extraction integrability over fi- nite budgets. Furthermore, we unpack “depletion time” into three mutually non-interchangeable concepts: gross turnover intensity, a frozen-rate local ratio, and a scenario-conditioned hitting time equipped with uniform-drift bounds. We classify three widely cited public-data indicators within this taxonomy: the G3P ground- water anomaly index is shown to be a record-relative statistical metric rather than a physical stock ratio; the USGS phosphate reserve-life ratio is an arithmetic convention of an economic class rather than an exhaustion forecast; and fisheries removals-only timescales represent gross pressure scales rather than demographic depletion diagnostics. We prove that no nonnegative linear weighting can universally certify componentwise nonnegativity on arbitrary balance do- mains, and we establish five double-counting rules to prevent the emergence of phantom mass. Finally, we formulate first-passage semantics on declared stochastic surrogates against record- relative barriers alongside explicit non-claims. The argument separates two questions often compressed into “weak versus strong sustainability”: whether material cycles close at demanded throughput—a state-conditioned dynamical feasibility question—and whether an assessment is scalar-compensatory or componentwise—a certification-semantics question. A stationary bridge between them is proved, but the two distinctions are not identified.