What maintenance task should be performed on NVGs after prolonged use?

The maintenance task that should be performed on night vision goggles (NVGs) after prolonged use is to inspect for scratches and damage. This is crucial because the optical components of NVGs are sensitive and can easily be compromised through regular handling, exposure to the environment, or normal wear and tear. Scratches or any damage to the lens can significantly affect the performance and image quality of the NVGs, making it harder to see in low-light conditions. Performing this inspection ensures that any issues are identified early, allowing for repairs or replacements to be made before the device is needed in critical situations.

In contrast, while recharging the batteries, cleaning internal parts, or upgrading software could be important maintenance tasks, they are not specifically aimed at ensuring the integrity and functionality of the optics, which is essential for NVGs' operational effectiveness. Recharging is routine but does not address physical wear; cleaning internal parts without proper guidance can potentially damage the device; and software upgrades, while beneficial, do not directly relate to the condition of the device's physical components after extensive use.