Focus on identifying physical damage and confirming the gate and locking system work properly. Start with a thorough visual check: look for any deformation in the carabiner body or gate, cracks, burrs, sharp edges, or misalignment between the gate and spine. These signs can indicate the strength has been compromised or the rope could snag or wear abnormally. Next, verify the gate closure and locking mechanism. The gate should close cleanly and fully, and the locking sleeve should move smoothly, engaging securely without sticking or cross-threading. A gate that doesn’t close properly or a lock that doesn’t engage means the carabiner could unintentionally open under load. Also assess for cross-loading signs. Carabiners are strongest along the spine; loading them along the gate or in a twisted or sideways manner reduces strength and can lead to failure. If the load path looks off or the carabiner is carrying load in an unsafe orientation, retire it. Finally, perform a quick functional test: operate the gate several times, engage and disengage the lock, and apply a light tug to ensure it stays closed and locked. If you detect any damage, rough operation, or failure to lock, remove the carabiner from service. Other options don’t provide a reliable safety check and can be dangerous or misleading.