*But OP - the same people who tell you that they find Sainsbury's too extravagant for clothes will forget to tell you that they keep three horses.
Those who boast of only ever buying job lots on eBay won't mention their brand new Range Rover. Half the people sniffing that they'd never pay outrageous prices for 'designer' clothes are paying school fees or a retinue of tutors.
What I'm saying is that if you do genuinely want some moral or financial guidance on the relative value of a particular, elective purchase you're not going to get a reliable answer from the question you've asked.
(And it touches a nerve with me. I hate this oblique belittling of women's expenditure.)*
Yes, that's why people don't usually spend £700 on a single item of clothing, because they've spent it on horses or rangerovers or private school. Of course.
Look, it's obviously down to individual incomes and expenses and priorities but even a millionaire would know that the VAST majority of people could not afford to spend £700 on a dress. And even the most ARDENT clothing enthusiast would know that, even if someone had £700 burning a whole in their pocket, most people probably wouldn't choose to spend it all on a single dress.
If people can afford to spend £700 on a dress and they want to do so, then fine. It's their money and they can do what they like with it. But there is no reason they should be blind to the fact that it is unusual.
I'd extend the same sentiment to people spending thousands on watches or antiques or whatever else. If a man spent it on clothes, I'd apply the same to him.