One of the biggest indicators to me, as someone who has navigated such lines before, is how comfortable co-workers are with waste. A co-worker who takes catered food home (without saying something like, "oh I have 3 growing teenagers" or something else to excuse it) is low-class. Do you keep the little sauce packets, napkins, disposable cutlery, etc. from take-out? Low class. Do you keep the pencils and notepads etc. from places? Low. Class. Also this causes you to need to have a place to store all these things, and now you fulfill the stereotype of a poor, messy person.
Minimalism, aka the confidence to be able to acquire anything you may need at the moment with resources always available to you, is a class indicator.
Minimalism, aka the confidence to be able to acquire anything you may need at the moment with resources always available to you, is a class indicator.