I've been building a better quality work wardrobe over the last year or so. I've changed where I shop, but I'm also paying more attention to fabric types and stitching quality. Even the new shops I've embraced have some very expensive polyester lurking amongst the nice things.
I'm also 29, btw. Here's where I've been shopping...
Hobbs. Their dresses and suits are too grown up for me, but I've picked up a couple of skirts in the sale, one thick woven cotton and one a wool-silk blend. They're lovely - and did a good job of 'lifting' my old polyester blouses while I was in the transition phase ;).
Jigsaw. For elegant silk tops, shirts and blouses to tuck into the skirts mentioned above. Again, in the sale, because at full price my budget wouldn't go far at all.
John Lewis. Particularly their pure collection for blouses and jumpers.
H&M. Yes, seriously! But I shop in store, try everything on before I buy, and check thoroughly for wonky seams and trailing threads. I have two great pairs of slim fit cotton trousers with a bit of stretch, and a couple of acceptable tops.
Woolovers for jumpers in wool and silk-cotton blends. I don't buy pure cashmere because I know from experience I can't make it last long enough to justify the price.
I've also been looking at Reiss, Whistles, Jaeger, LK Bennet, and a couple of local boutique type shops. I've seen a few things I like but now I have the essentials I need to watch my spending for a while! I now have my two skirts, 2 trousers, about 7 tops, a wool blazer (Mum's old work wardrobe - sorry!), and a couple of jumpers (1 v-neck and 1 round-neck) as the basis of my work-wear. They more or less all mix and match in greys, blues, pinks, and ivory, plus a rogue red blouse.
This all sounds scarily expensive, but by carefully choosing one or two really lovely things each month, I no longer want to spend money on bad quality clothes. I'm not having to replace dresses that shrink when they're washed (Dorothy Perkins) or tops that unravel at the seams (Zara) either. And I actually like how I look in my clothes.