Authenticity is the cornerstone of the pre-owned luxury market. Buyers must demand third-party authentication certificates (e.g., Entrupy or Real Authentication) and detailed high-resolution photos of date codes, serial numbers, stitching patterns, and hardware engravings. Condition should be graded based on international standards: N (New), SA (Excellent/Mint), A (Very Good), and B (Fair). Ensure the supplier provides a comprehensive condition report highlighting any scuffs, interior odors, or hardware oxidation.