I don't buy super-high-end clothing because I'm above a size 14 and designers tend to ignore people who are built like me, unless you have major $$$ like Oprah Winfrey, Marjorie Gubelmann and Queen Latifah..
Most of my "expensive" clothing comes from bridge designers such as Linda Allard/Ellen Tracy and Dana Buchman. I tend, however, to buy things on sale and at places like Off Fifth Saks Fifth Avenue and Nordstrom Rack. For instance, I've found $200+ pieces for $50 or less.
I buy this stuff because I'm single and have no attachments, and will be inheriting my home. If I ever get married and have kids, I suspect I will be wearing T-shirts and casual pants because I don't want a baby messing over my silk shirts.