When selecting glass doors, the most critical factor is the type of glass. For safety and durability, prioritize Tempered Glass (Toughened) or Laminated Glass, which are significantly more resistant to impact than standard glass. Pay close attention to thickness, typically ranging from 8mm to 12mm for frameless designs. Additionally, verify the hardware material; high-quality 304 or 316 stainless steel or anodized aluminum is essential to prevent corrosion and ensure smooth operation of hinges and rollers.