This topic gets more interesting.
I agree 100% with Jenn. She is very right in saying "I think you have to be at the right place in your journey, confident in your style and judgement, to implement it." And since I see you as someone with an evolved sense of style, Dehorah, this could be a great strategy for you to shop.
However, the more I think, the more I realize a few more things. Some people have a classic dressing style and choose pieces that are classic in styling. These pieces do not look dated for quite a few years. However, even a really well made pencil skirt or structured dress starts to look dated after a period of time.
I can think of my husband as another example for strict shopping. He buys fewer than 5 pieces a season. Sometimes none at all (particularly winter). He knows what looks good on him and chooses his clothes very carefully. He's also very very fussy. But once he has a piece, he wears it well and he wears it often. He's one of the best dressed men I've ever met, so that's saying something. He wears formals well and wears casuals equally well. He only updates his wardrobe once a few pieces start to wear out. He makes do with fewer things until he decides it's time to go shopping and will replace everything old in one go. So one season this could be formal trousers, or jeans, or shirts or even shorts. This strategy works well for him somehow. He also never looks at cost when shopping. He buys so rarely that he doesn't mind spending more at all. Strangely, he never shops in sales. He thinks he's worth full price and also believes that when you pay more, you tend to value things more and choose more wisely. I don't always agree with this philosophy, but it works for him.
On the other hand, those who like to follow trends may not always be able to make do with just 5 pieces every season. From what I've noticed, some seasons the new trends hardly differ from past years, some seasons you see a dramatic change. So restricting oneself to 5 pieces may not always work. I think in the end it all boils down to personal preference. Some people can mix a trendy item with old things (example Angie herself, and you too) and transform the whole outfit for it to read current. Some people can't do that at all and feel 'stuck'.
Also, for those of us who deal with weight fluctuations, this may not always be possible. I know people who actually have three different sizes in their wardrobes coz their weight fluctuates that much. A quality piece that fits well is of no use if you tend to gain weight with seasonal changes....coz then the item will only fit well sometimes. My weight fluctuates quite a bit too with hormonal changes, so that's possibly another reason why I need a larger wardrobe.
Like Viva, I just want to make wiser choices, and that will be enough to make me happy. I want to sit back and think before I buy, be able to justify the purchase and not just say 'Oh but it's so pretty!' and be able to practice some degree of restraint. If I can do that, and I have started to do this, I'm sure I'll be happier with the things that come into my wardrobe. I buy clothing and accessories very often, but I've started to notice that I'm more picky. That also means I'm getting more obsessive and aggressive with my search, because patience isn't one of my stronger virtues. Now that I know I want to buy muted silver sandals next, I am hunting down the perfect pair and don't want to settle. I have a mental image of what I want and I want just that! A year back I would've picked up any pretty pair...experimented...then bought another one until I finally found one that was pretty and comfortable at the same time. Today, I want to start by buying a pair that's perfect already and don't want to keep looking for the same thing over and over only because I want immediate gratification. I think that's progress. And for now, I'm happy with just that.