I had to have my hair up and above my collar when I was in the Forces. Off duty, it was loose. Now, if I am going somewhere format I do put it up, particularly if needing to wear a hat or fascinator, helps to keep the headwear in place and looks smarter. As soon as the informal part starts, then down it comes. I did wear it up for my graduation. I also use an organic colour. Cannot use chemical versions, but the organic variety works well for me.