Aside from the functional purposes, i.e. blocking the sun/for sports/cold, is it ever okay wear your collar turned up?
As I write this, dear reader, my collar is popped. I am sitting at my desk, indoors, and yet it is completely okay for my collar to be turned up—because this collar calls for popping. Now, before people start calling for my head (and my neck is protected, so remember to swing the axe extra hard), let me say that collar popping should be mostly relegated to jackets; any overcoat is fair game, as is a blazer provided it’s of a sturdy material. While a suit jacket is a no-no, a jean jacket or a field coat are without question poppable, and don’t make me even talk about peacoats. A turned-up collar on a jacket seems more natural than on a shirt, so focus your flipping there—unless the shirt you’re considering putting the pop on is made of a sturdy material (heavy flannel or a rugby shirt come to mind). Truth is, popping one’s collar on anything other than a polo (which you should never do, that’s been ruined) comes down to personal preference, and you must carry it with absolute confidence. Ask yourself, “Can I pull this off?” And if there is doubt in your heart, it’s probably best to avoid it. Unless it’s a peacoat: Then there’s no excuse.