When was the only time Celts wore helmets?

The Celts are known to have worn helmets primarily during battle, particularly in the context of warfare from the 4th century BCE onwards. Archaeological evidence, including finds from burial sites and battlefields, indicates that helmets were used in various Celtic cultures, especially in regions like Gaul and Britain. These helmets often featured distinctive designs and ornamentation, reflecting the status of the wearer. Overall, helmets were not everyday items but were reserved for combat situations.