Request samples to inspect for air bubbles, scratches, or uneven thickness in the glass, which are signs of poor quality control. The electroplating or spray-painting finish on the base or glass should be tested for adhesion and scratch resistance. For B2B orders, specify a maximum allowable defect rate (AQL 2.5/4.0) in your contract to ensure consistency across large batches. High-end models often feature hand-blown glass, which offers a unique aesthetic but requires stricter quality checks on dimensional tolerances.