When evaluating quality, focus on the denier count of the nylon fabric (e.g., 210D, 420D, or 600D), as higher denier indicates better durability and tear resistance. For the zippers, ensure they are Grade A nylon coil zippers with a smooth pull action; #3 zippers are standard for small pouches, while #5 zippers are preferred for larger tote bags to ensure longevity under load. Additionally, check the stitching density, aiming for at least 6-8 stitches per inch to prevent seam failure during heavy use.