Prioritize footprint location relative to ports and major routes, WMS and API integrations, SLA performance for picking/packing, inventory accuracy metrics, returns handling capability, and the 3PL's carrier contracts and reporting. Evaluate scalability for seasonal peaks and the provider's experience with your product temperature and compliance requirements.

Labor rates and storage density drive unit picking cost and storage per-SKU; cross-dock and consolidation options reduce transportation spend. Consider throughput assumptions, order profile (lines per order), and peak staffing costs to model cost-per-order and landed cost. Evaluate TCO including transport, duties, and inventory carrying costs.

Compare parcel and LTL transit time averages and variance, on-time performance, cut-off times, intermodal schedules, and frequency of sailings or dray runs. Require real-time tracking, exception reporting, and standardized KPIs (OTD, inventory accuracy, order cycle time) to ensure visibility and control across corridors.