Cutting RAG inference costs 6x starts with deciding what never reaches the LLM

Organizations can reduce RAG inference costs by 6x by implementing a three-stage cascade architecture that routes only genuinely ambiguous cases to LLMs, with deterministic rule-based logic and targeted retrieval handling the majority of decisions. This approach is critical for regulated enterprises where auditability, consistency, and cost control are non-negotiable—all-LLM pipelines fail under compliance scrutiny and accumulate hidden costs at scale while introducing unpredictable model drift on straightforward cases. IT leaders must redesign their evaluation metrics and prompt engineering to account for asymmetric risk tolerance rather than treating all errors equally, transforming the LLM from a front-line processor into a controlled escalation layer.