The main concern I have with fashion editors and magazines et al bestowing great virtue on quality style purchases, is this is determined by your available income.
I've read up and digest all the differing views on this matter and it basically distills down to one fundamental point - your disposable income. The problem is you have to choose what you buy very carefully if you have very little or no disposable income.
Think about planning your wardrobe as a map - a map of activities. If you are a stay at home mum for example then you need more casual clothes than going out items. I would recommend you buy more items but at lower prices for things around the home, a couple of easy but fashiony school run items and save up to buy a gorgeous dress and bag for going out. Make the dress a stylish designer number and the same with the bag. You have a special item to pull on for dinner dates, drinks with girl friends and an item you can keep. The idea is whether you are working, young carefree or burdened down by responsibility or mortgages, then plan your basics and build the fabulous stuff in year by year.
I think the less is more approach allows you to have goals and these goals mean carefully selected items that you will keep. TK Maxx and thrifting at charity shops and car boot sales are a great way of getting individual well made items by great designers.
As a rule of thumb I always keep any designer item I've bought and I include certain high quality retailers like Joseph in this category. But I do not buy overtly high fashion items from designers otherwise their glitz fades. And this is always a hard one to qualify or agree on but sometimes certain garments are of a moment and unless you've got money to burn be careful.
I bought a silver maxi skirt from Kate Moss's first Topshop collection which I was always keep and I have a New Look leather jacket which is a winner as it is very 70s and always comes in handy - but these are exceptions. I tend to wear out and never keep most of my high st buys in the long run. Although I don't buy expensive white tee shirts and I've had a Gap one for years.
Choosing style and slow fashion over the immediacy of trends and a jam packed wardrobe is quite hard but with planning, wardrobe mapping and a bit of patience fabulous pieces that work year in year out can be yours.