User blog:Astraea8/Castiel´s trenchcoat

So I know that Castiel´s trenchcoat, shirt, and tie are his signature look, but has there ever been any explanation for why Castiel always wears the same clothes? He wore a sweater when he was Emmanuel and didn´t remember that he was an angel. He wore a uniform as ¨Steve.¨  Other angels change clothes. Just curious.