Vendor price drift
Supplier pricing rarely increases in one dramatic jump. It creeps — a few percent per invoice, across multiple line items, over many months. No individual change triggers a review. But when you plot cost-per-unit over time by vendor and category, the cumulative impact becomes clear. In our engagements, we regularly find 8–18% cost increases from vendors that were never formally approved or renegotiated. The fix is a data-backed conversation, not an operational change.