In my quest to make my wardrobe smaller and more functional, I want to buy good quality garments that will last. I know silk, cashmere, wool and tweed are all quality fabrics (although there seems to be differences in quality among brands). I'm wondering about things I've been reading on the label like viscose, rayon, polyester, etc. Are there any that are usually pretty poor and should be avoided? Are certain ones that are mixed with say wool or silk better? And which ones are easily cared for?