I think as a side note, there is too much disingenuousness around the 'Goodness! Social markers? I just wear any old thing and so does my husband!'
Social markers are definitely a thing - you may not know that, or recognise it as such, but they exist. Red/Salmon/Pink/Mustard trousers are absolutely a thing amongst a certain suburban/country set as well as in London among what would previously have been called Sloane types. Also a fashion thing for younger men -the two sets are completely different (although there may be some overlap on the social marker venn diagram, should such a thing exist...)
The vast majority of people, consciously or not, dress, speak and behave in certain ways so that they give out visual/audible signals that they belong to a certain group/subsection/class. Humans are tribal, we like to recognise 'one of our own' and clothes are a huge part of how this happens. Even people who say ' I don't take any notice of that kind of thing' are giving out the signal that 'they don't care' and as such are taking an implied high ground abover people who 'care'
It IS exhausting, of course, but denying that such tribalism exists is daft. By and large we ALL make judgements about people based on what they wear. Once you know you are doing it you can try and modify your triggers, but it's hard to go against a life of subconcious judgement. For what it's worth, I do judge middle class, midde aged red trouser wearing men because in my experience, they have not been the kind of people I have tons in common with. It's a shorthand we all use to some extent, whether it's accurate or not.