Focus on measurable KPIs: order accuracy, on-time dispatch rate, inventory turnover, dock-to-stock time, and cost-per-order. Also evaluate SLA remedies, tech integrations (WMS/API), peak capacity planning, and carrier relationships that influence transit reliability.

Run a landed cost model comparing storage, pick-and-pack, inbound/outbound freight, and return handling. Factor in service-level differences (same-day vs. standard), labor seasonality, and inventory holding days to calculate cost per order and margin impact.

Verify road quality, access for full trailers, yard capacity, and cross-dock capability. Confirm carrier contracts and frequency, last-mile coverage maps, and ability to handle intermodal transfers. Inspect security, power redundancy, and dock configuration for throughput needs.

Prioritize WMS with real-time inventory APIs, EDI or modern API connectivity to eCommerce platforms, barcode/RFID support, and reporting dashboards. Ensure the 3PL can support automated order routing, cartonization logic, and returns processing workflows.