In the case of ‘big brands’ it is almost certainly a prestige thing. Loads of ‘designer’ stuff is completely, garishly disgusting. However, some labels do stand for quality (I won’t go into cars), and though you might pay disproportionately more for them, you are guaranteed a certain level of quality.
For example, Ray Ban sunglasses might last 20x as long as the cheap rip-offs, but they do cost 50x the price.
On the other hand, if I’m looking for some designer sunglasses, I will start off with a brand I have previously owned, because they are more likely to have more styles to my tastes.
But then you also have things like your Rolex, Rolls-Royce, Savile Row suit, which ‘send a message’.
in the case, of the ‘latest trends’ in what I would call pop-commercial-fashion, that’s just people with little imagination and a strong desire to ‘fit in’ See: most teenage girls. Even those that are anti-fashion seem to subscribe to some kind of ‘anti-fashion’ (Hey, I was most certainly guilty at 13)
Now I am still anti-fashion, I only ever acquire my clothes from ‘thrift’ or vintage or second-hand or charity stores/stalls, preferable in a foreign country, preferably thousands of miles away, and preferably for a ridiculously low price. Imagine my fury when those ‘hipsters’ suddenly made ‘vintage’ somehow kind of pretentious and sought-after! The average price of my shirts has gone from £1 to £10!! =P
And yes, this makes me a guy who might be wearing a £4 pair of shoes, a £1 pair of trousers, a 50p shirt and £80 sunglasses, but hey, a great shirt can still be great 40 years on, so for 50p that’s, well… great. Sunglasses, on the other hand…