Prioritize WMS compatibility and API/EDI connectivity, inventory accuracy, pick-and-pack throughput, returns handling, cross-docking, and value-added services (kitting, labeling). Assess SLA metrics (OTIF, order accuracy), reporting cadence, and scalability for peak seasons to ensure the provider can support omnichannel flows.

Proximity to primary highways and rail terminals enables shorter overland transit to neighboring markets and more consolidation opportunities. Higher carrier density and intermodal choices reduce lane volatility and enable better negotiated rates. Evaluate common lanes, consolidation frequency, and direct versus hub routing to estimate lead-time and cost impact.

Expect storage fees (per pallet/m2), per-pick and per-order charges, inbound/outbound handling, and extra fees for value-added or temperature-controlled services. Key cost drivers include SKU mix, density, seasonality, labor skill, and SLA strictness. Negotiate volume discounts, minimums, and transparent pass-through freight terms.

Many providers offer customs brokerage, bonded or duty-deferred storage, HS classification support, and importer-of-record services. Verify brokerage licenses, transit and declaration capabilities, AEO or equivalent accreditations, and the 3PL's interface with your customs broker to ensure compliant cross-border movement.

Include OTIF, order accuracy, inventory accuracy, dock-to-stock time, order cycle time, and damage/shrinkage rates. Also specify reporting frequency, penalty or remediation terms for missed SLAs, capacity allocation for peaks, and change management processes to handle SKU introductions or demand shifts.