Prioritize fill rate, order-cycle time, on-time dispatch, inventory accuracy, and reverse-logistics processes. Verify WMS/ERP integrations, slotting flexibility for mixed SKU velocity, carrier contracts for last-mile and LTL, and scalable labor arrangements to cover peaks and promotions.

Focus on proximity to arterial routes and ports, frequency of scheduled carrier collections, cross-dock capabilities, and established freight lane relationships for UK and ROI movement. Confirm customs handling, bonded storage options, and carrier SLAs aligned to your transit-time targets.

Key cost drivers include storage density (racking vs bulk), pick labor productivity, transportation miles to major markets, IT integration fees, and seasonal labor premiums. Evaluate pricing models—per-pallet, per-pick, pick-and-pack tiers—and forecasted volume to negotiate blended rates.

Scaling speed depends on the provider’s spare warehouse capacity, labor pool access, flexible shift patterns, and WMS scalability. A mature 3PL can ramp headcount and introduce temp storage within weeks; validate turnaround with documented onboarding timelines and contingency plans.