edit - I'm not talking about blazers. Alright, I know that when you buy a suit, you get a matching jacket/pants. But how do you know when a jacket can be worn with jeans/khakis or when it has to go with a matchinig pair of pants? I'm talking about when you buy a stand-alone jacket in a store like H&M, or Express, or Bach Rach. Some of them are wool and look like suit jackets, except they don't come with matching pants... so does that mean you can wear them with some other pants? Others are like corduroy... and I'm assuming you wouldn't wear those with matching corduroy pants Here let me itemize my questions for you: 1. How do you know when a jacket is ok to wear with jeans or khakis and doesn't require a matching pair of pants? Is this determined by the material from which it's made? Or the color? A combination or both? Something else? 2. Are there specific rules with regard to color/material matching, like "don't wear x color jacket with y color shoes," or "don't mix material a jacket with material b pants" or anything like that?