As far as you can and your expertise allows you to be.

Unfortunately, price no longer determines super duper quality. You have to assess the quality of an item yourself, and run with it. Re-read this post for tips:

I've been ordering in some designer items that tickle my fancy, and am terribly disappointed with the quality. Makes me angry.

#1 - What I thought would be a gorgeous quality skirt. It had such potential and I was ready to splurge - but what a disaster. Absolute schmutters, I can barely believe it. I checked before I purchased to make sure it wasn't 100% viscose. It's not. You could shoot peas through the fabric, the ruffles did not lie flat, the seams were puckered, the gathers were badly stitched, and the inside of the garment looked like I sewed it (I'm a terrible seamstress). Mega nasty, and with tax it costs $490. I wouldn't want the skirt if you gave it to me for free.

And in sharp contrast at a fraction of the price:

#2 - A Boden shirt that is IMPECCABLE. French seams, piping, gorgeous fabric, stunningly stitched, launders beautifully. $65.

#3 - A BR fuzzy jacket that is GORGEOUS and very well made too. Beautifully stitched, inside bound seams!!!, fuzzy fabric that does not molt or get into your nasal passages, fab stretchy fabric, great drape and structure, perfectly symmetrical pockets, machine-washable. $123.

#2 and #3 earned a place in my wardrobe. Both items showcasing excellent workmanship.

My point is not to discard designer wear. Not at all. If that floats your boat - enjoy it! There is beautifully made designer wear. My point is to be DISCERNING about quality at every price point because that is sustainable.