When sourcing mixed items, the most critical factor is the supplier's consolidation capability. You should prioritize suppliers who offer one-stop sourcing services, allowing you to combine different product categories (e.g., electronics, home goods, and apparel) into a single shipment. Ensure the supplier has a robust Quality Control (QC) system to inspect diverse product types, as defect rates can vary significantly across different categories. Additionally, verify their MOQ flexibility, as mixed orders often require lower quantities per SKU to manage inventory risk.