Require clear KPIs and SLAs for order accuracy, on-time shipment, inventory accuracy, pick & pack lead time, and returns processing. Include penalties/credits for SLA breaches, monthly reporting cadence, root-cause analysis for incidents, and provisions for seasonal volume and surge capacity.

Map customer delivery density vs. warehouse locations, analyze transit-time contours, and model split inventory scenarios. Evaluate racking types, dock-door counts, value-added services, and WMS/OMS integrations to confirm the 3PL can scale with peak demand and omnichannel routing rules.

Look for multimodal connectivity, dedicated truck yards, bonded storage or customs facilitation, strong local carrier relationships, real-time freight visibility, and documented cross-border experience. These elements reduce transit variability and simplify compliance for B2B flows.

Include warehousing rent and labor, inbound and outbound freight, inventory carrying cost, returns handling, customs/duties, last-mile delivery rates, and potential stock obsolescence. Run scenario-based models (volume, SKU mix, and service levels) to quantify trade-offs.