There is no definite fashion rule when it comes to wearing flag belt buckles. In today's world, it is fortunate that we are no longer constricted in manners of clothing since the trend nowadays is geared more to individualism. Though there are trends where people can follow, most fashion gurus prefer if a person shows one's personality than mimicking other people's style. It is true that there are no more rules when it comes to wearing your accessory. As long as it matches your overall outfit, then it will do fine. However, we have to consider that there are certain designs which may not be appropriate to certain outfits. Take for example a rodeo American belt buckle; the casual design may not be appropriate for formal wear consequently to formal occasions. That also follows that some formal flag belt buckles, such as the gold metal buckles, may not be appropriate for laid-back outfit.