Which of the following is NOT a valid reason to discard a carabiner?

The option that indicates the gate sticks or closes sluggishly is considered not a valid reason to discard a carabiner because a carabiner can still function effectively even if it does not operate as smoothly as it should. The primary function of a carabiner is to maintain a secure connection, and as long as the gate can still achieve a positive engagement and is not in danger of opening unintentionally, it may still be usable.

In contrast, a bent carabiner, a broken latch mechanism, or a broken gate spring all compromise the carabiner’s structural integrity or its ability to lock properly. These conditions present significant safety hazards. A bent carabiner distorts its shape and can lead to unpredictable loads, while a broken latch mechanism can result in accidental disengagement during critical operations. Similarly, a broken gate spring prevents the gate from functioning correctly, leading to potential safety failures.

Therefore, while sluggishness could suggest wear or the need for maintenance, it does not inherently indicate an immediate failure in the carabiner's basic function, distinguishing it from the other reasons that indicate critical impairments.