Request third-party lab test reports covering tensile strength, colorfastness to light and rubbing (ISO 105-X12), and waterproofing grades (IPX4 or higher). A critical test for travel gear is the jerk test, where the backpack is loaded to its maximum capacity and dropped repeatedly by the handle; ensure the supplier meets a standard of at least 400 cycles without seam failure. Additionally, verify stitching density, which should be 7-9 stitches per inch with bar-tack reinforcement at all stress points like strap attachments.