When sourcing from Thailand wholesale traders, prioritize material authenticity and durability. For leather footwear, ensure the use of genuine top-grain or full-grain leather rather than bonded alternatives. For athletic or casual shoes, verify the density of the EVA or rubber outsoles to ensure slip resistance and wear longevity. It is critical to request material safety data sheets (MSDS) to confirm that adhesives and dyes are free from harmful chemicals like lead or phthalates, especially if the target market is the US or EU.