Prioritize metrics that reflect throughput and accuracy: order lead time, pick-and-pack accuracy, dock-to-stock time, inventory turnover, and on-time dispatch rate. Also evaluate SLA remedies, reporting cadence, and system integration (WMS/API) to ensure visibility and rapid exception handling.

Carrier density reduces transit variability and often lowers bid rates on regional lanes. Assess the 3PL's carrier contracts, LTL consolidation practices, and ability to tender to multiple carriers to optimize cost per parcel and maintain consistent delivery windows.

Look for segregated picking zones, scalable racked storage, configurable packing stations, returns processing, and cross-dock operations. Integration with your OMS, support for variable cartonization, and weekend/peak staffing plans are essential for omnichannel performance.

Key cost drivers: storage rates (per pallet/sku), pick fees, inbound receiving charges, putaway, and minimums. Control costs by standardizing packaging, improving forecast accuracy, consolidating SKUs to reduce active storage, and negotiating volume tiers or shared services.

Evaluate the provider's footprint flexibility, surge staffing model, multiple facility options in the network, and the ability to implement additional services (kitting, light assembly). Confirm contractual exit/expansion terms and data portability to avoid operational disruption during growth phases.