We introduce quantum information copy time as a task-defined latency for transport: it is theearliest time at which a receiver confined to a region B can certify, with prescribed advantage,which of two global hypotheses was prepared by local operations in a distant sender region A.The benchmark definition is information-theoretic—the Helstrom advantage on B, given bythe trace distance between reduced states—and it admits natural refinements that incorporateexplicit measurement restrictions (few-body and moment channels). We first derive kinematiclocality constraints for Hamiltonian/Lindbladian dynamics with Lieb–Robinson tails and forcircuits/quantum cellular automata with strict light cones. We then establish a theorem-leveldiffusive benchmark in the quantum symmetric simple exclusion process (Q-SSEP): for locallyprepared charge-biased hypotheses, the Helstrom copy time obeys an unconditional diffusion-limited lower bound expressed in terms of the diffusion constant Dand the static susceptibility χ.For closed Hamiltonian systems we formulate, with assumptions stated explicitly, a projection-based route that ties restricted copy times to a single slow transport pole on a diagnosticallycheckable time window. We provide conservative exact-diagonalization diagnostics in the XXZchain together with a bundled TEBD/MPS reference implementation and convergence protocol(Supplementary S2 and Code SC1), validated against exact evolution on small sizes; large-LTEBD studies are left as future work. Finally, we contrast copy time with scrambling diagnosticsbased on out-of-time-ordered correlators and identify regimes in which conservation laws delaycertifiability well beyond the ballistic operator-growth front.