When Does Memory Orchestration Help a Strong LLM? An Efficiency Law and Certified Representation Levers for Long-Term Memory

We ask when adding a memory-orchestration layer around a strong LLM actually helps, and when it does not. Across controlled multi-vendor experiments we derive an efficiency law separating the regimes in which orchestration pays from those in which it is neutral or harmful, and we certify four representation-level levers that survive the stricter regime: date-anchored rendering, consolidation memoranda, cheap consolidation that outperforms full re-processing across vendors, and a value-of-information gate. Negative and null results are reported in full: several intuitively appealing configurations do not compose. The contribution is a decision rule for practitioners — orchestrate here, do not orchestrate there — grounded in measured effect sizes rather than architectural preference.