The consequences could be far more serious than when a rein or stirrup leather lets you down, yet riders tend to pay much more attention to the rest of their tack. Unfortunately there are hundreds of poorly manufactured bits for sale in every tack shop, but the cheap foreign bits are more difficult to spot compared to inferior leather goods. These pictures all show bits which can be bought from tack shops, most of them were actually in daily use, and presented a real danger to the lives of the riders using them. Look how badly this bit has been finished off. It can only cause discomfort to the horse.
Gas bubbles in the metal cause an area of weakness, and are a sign of poor manufacturing.
Rubber bits should not be left in direct sunlight and need replacing every two - three years. Also every rubber bit should have a chain through the middle for safety. Many retailers remove the packaging before putting bits on display, so with an unbranded product you won't know where it has come from. This poorly crafted joint would pinch a horse's lips badly. Note also the faults in the metal.