Prioritize throughput (orders/hour), order accuracy, inventory accuracy, on‑time ship rate, and average order cycle. Verify WMS compatibility, API/Webhooks for real‑time inventory and order sync, EDI support for B2B lanes, and reporting dashboards. Confirm SLA remedies, peak staffing plans and visible exception handling for returns and chargebacks.

Proximity to major corridors and carrier hubs reduces miles, transit days and zone counts—lowering parcel and LTL rates. High carrier density enables competitive tendering, zone‑skipping and consolidated LTL moves. Evaluate the 3PL's negotiated carrier contracts, drop‑trail options and ability to optimize routing for your dense customer zones.

Compare storage (per pallet/shelf), pick‑and‑pack (per pick, per order), receiving, returns, special handling, dimensional weight rules, minimums, billing cadence, IT fees and any SLA penalties. Factor in inbound freight handling, seasonal labor surcharges and expected variability to model blended cost‑to‑serve by SKU and channel.

Prioritize dock door counts, clear height, racking density, automation readiness, cross‑dock capability, dedicated returns processing and kitting/assembly areas. Validate workforce scalability, onboarding speed for seasonal staff, proximity to key customers, and the 3PL's experience with peak ramp plans and contingency for carrier disruptions.