I want to know the answer to the following question:
What is only worn for very specific occasions?
All the background I'm provided with is that "The navy, most army, and some other units have, for very specific occasions, a ceremonial/regimental full dress, such as the naval "high-collar" white uniform, kilted Highland, Scottish, and Irish regiments, and the scarlet uniforms of the Royal Military Colleges.". Is that enough to answer the question?