I would like to know what type of clothes makes a person appear thinner. I took an apparel and design class and we learned about colors that flatter people. Black and white are neutral colors and I think they make everyone seem thinner. And avoid tight clothes because they will draw attention to your larger parts. Calif. Things go out of style fast because designers are always designing new clothes.
People get tired of their old stuff because of all the cool new designs that comes out.
You should really base your style on the stuff you like and forget about what everyone else thinks is trendy at the time. If you're a guy, you should always wear a tux. Renting is the cheapest, but buying one may be a sound investment if you plan to get season tickets to the Opera. If you're a girl, you should wear a formal dress, but not like a prom dress. Something elegant and sophisticated, maybe something in black.