Very daft thread title i know.
I don't need to know this because I want to emulate it or copy it. I'm not interested in looking rich, I could make the most expensive item in the world look like a bin bag, hehe 
But have been in a conversation with my sister who believes rich (or very well off) people don't feel the need to worry about clothes or style so wear very basic, ordinary (even cheap) clothing during the day or school run, etc but get the really expensive stuff out for special occasions and specific pursuits only. So basically you would never guess from the clothing if a person was very well off (generalisation alert!)
My opinion is a bit different in that I would imagine you can enjoy playing with style and might prefer to express your identity with lovely quality pieces, like we all might (depending on our budget). So I mainly presume we are all essentially the same, just having different incomes.
I must admit that having once lived in a wealthy part of the UK a lot of people did tend to just bob about in jeans, tshirt and converse. But that was years ago,
So which is it? P'raps it differs across the UK?