Prioritize order cycle time, inventory accuracy, dock-to-stock time, picking productivity (lines/hr), on-time-in-full (OTIF), return processing time, WMS uptime and API availability, and billing transparency. Use baseline audits and SLA scorecards to compare providers consistently.

Key cost drivers include per-pallet storage and tiered density, per-pick/pack handling fees, inbound receiving charges, value-added services (kitting/labeling), returns processing, minimum monthly fees, WMS access charges, and accessorials such as demurrage and fuel surcharges. Model cost-to-serve by SKU velocity and seasonality.

Require a WMS with real-time inventory APIs or EDI, native or partner OMS integrations, barcode and mobile scanning, configurable rule-based order routing, and reporting dashboards. Confirm sandbox integration, uptime SLAs, and event-driven notifications for exceptions.

Assess proximity to national highways and railheads, access to express parcel hubs, carrier lane density, dock and cross-dock capabilities, local labour availability, lease and tax considerations, and the provider's carrier contracts. Run a cost-to-serve model and transit-time analysis for representative zip-code cohorts.