Focus on measurable KPIs: average order turnaround, dock-to-ship time, inventory accuracy, and on-time pickup performance. Also evaluate facility specs (clear height, racking, cold storage), WMS/ERP integrations, labor flexibility, and carrier connectivity to ensure the 3PL supports your SKU mix and service-level expectations.

Model landed cost scenarios combining storage, handling, and outbound freight using your order profile. Compare transit time improvements from local hubs, parcel zone reductions, and multi-carrier rates. Include peak-season labor premiums, returns processing costs, and billing transparency when comparing proposals.

Require robust WMS with API connectivity to your OMS, order routing, real-time inventory feeds, and reporting dashboards. Look for EDI or API for carrier labels and tracking, support for batch and lot control if needed, and role-based access for operations and finance teams.

Negotiate SLAs for order accuracy, pick/pack lead times, on-time dispatch, inventory reconciliation cadence, and damage/shortage resolution timelines. Include financial remedies for repeated SLA breaches and clearly documented onboarding timelines, capacity commitments for peak periods, and change-management processes.