I think it depends on what it is. I would/ do spend money on some really decent (well made, last a lifetime if looked after) things. Some bags, coats, shoes. Often they will be by fashion houses or by makers with pedigree. But I view them as a bit of an investment because they will last. I also have some wonderful things from grandparents and parents and such and other wonderful second hand finds - a glorious 1980s Gucci jacket for example. And I hope one day my children and grandchildren might potter down the Kings Road in something of mine.
And I think buying something that lasts is a very worthwhile thing. Better for the environment, made by trained professionals being paid a proper wage, rather than some child labourer somewhere, and it often ends up saving money in the long run: pair of shoes that last several decades and cost £800 or ones that barely make a season and cost £60 or something.
A few years ago Stella McCartney talked rather well on it on Desert Island Discs.
Of course buying sustainably and to last is sadly only a luxury those with some expendable income can afford. (What I find awful is those who can afford to buy better (at least avoiding cheap child labour, environmentally destructive fashion) and don’t.)
There’s a rather famous quote by the wonderful Terry Pratchett on the subject:
“The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money.
“Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of OK for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles.
But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that'd still be keeping his feet dry in ten years' time, while the poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet.
This was the Captain Samuel Vimes 'Boots' theory of socioeconomic unfairness.”
That said a lot of high end fashion places also make absolute shite that will barely last the season and are bought by (usually young people) with more money than sense! Personally, I would happily spend a lots on a coat or bag or shoes, but not anything like £800 on a pair of trainers that will die a death rather quickly.