Prioritize measurable SLAs (order-to-ship, pick accuracy), WMS/API integrations with your OMS and carriers, real-time inventory visibility, capacity for seasonal peaks, and returns/ reverse logistics capabilities. Also evaluate geographic coverage relative to your customer density and LTL/parcel lane frequency.

Proximity to major highways, port and airport gateways shortens transit windows and reduces drayage. Closer placement to customer clusters lowers last-mile rates and delivery time. Map delivery time distributions from candidate DCs to key ZIP codes and compare carrier zone rates to quantify impact.

Require a modern WMS with API/webhooks for order flow, multi-carrier shipping integration, real-time inventory and ASN support, EDI for B2B customers, and reporting tools for cost per pick, dwell time, and OTIF metrics. Ensure the 3PL can support multi-node inventory allocation strategies.

Key levers include reduced parcel zone charges via closer proximity to customers, lower inbound drayage and intermodal costs, inventory pooling to lower safety stock, and improved route density to drive per-shipment savings. Validate using a landed-cost and transit-time model across SKUs.

Assess historical peak performance, flexible labor models, overflow capacity agreements, seasonal sloting strategies, and cross-dock options. Review contingency plans for carrier disruptions and ask for references showing how the 3PL managed previous seasonal surges.