Lead time is a chain of handoffs
Production is only one part of replenishment. Materials, quality checks, booking, origin handling, transit, customs, preparation, delivery, and receiving can each add time before the unit becomes sellable.
Record planned and actual dates
- Purchase order and production start.
- Production complete and quality release.
- Carrier handoff, departure, and arrival.
- Customs release, preparation, and final delivery.
- First received and first sellable inventory date.
Use a range for each supply lane
Calculate typical and delayed outcomes by supplier, shipping mode, origin, destination, and season. Combining different lanes into one average can hide the exact route that causes the greatest replenishment risk.
Choose the buffer based on business impact
High-margin fast sellers may justify more protection than slow or easily substituted products. Review the buffer against stockout cost, carrying cost, cash limits, and the ability to use faster replenishment when a delay occurs.