Specific age bracket? Not really. They will almost all be adults (though some might be a bit younger, I suppose), I doubt that there are that many old people, and I'd guess most are young to middle-aged, but that might just reflect my ignorance or my stereotyping. I doubt if there is reliable demographic information available for this group, so I am just guessing.

Choice? Yes.

Just as a reminder, there is a mineral connection that you could pursue if you wish. Or not.

Connected with sport? Occasionally, but not necessarily.
Something that people have to wear? No (unless you go with extremely liberal interpretations of "have to" and "wear").