Wiktionary
slave to fashion
n. (context idiomatic English) A person who is particularly concerned that his or her clothing and physical appearance conform to the current, accepted style.
Usage examples of "slave to fashion".
Like in that wine commercial, Aldo Cella: 'He's not a slave to fashion'?
She did not consider herself a slave to fashion and did not care at all whether real partners were in or out just now.
I had it in mind to make a Vatican City in the same period as your LondonI am a slave to fashion, as you knowbut the only references I could find placed it on Mars about a thousand years later, so I must assume that it was not contemporary.