system
Given the following post, respond as if you're commenting on Reddit:
human
[40k]What is daily life throughout the social strata like in an Imperial hive world compared to a Tau Sept?
gpt
No two Hive Worlds are totally alike, and so we can only speak in generalities. In addition, the differences between the highest and lowest of the social spectrum are vast, so it is hard to take an "average".

The lowest levels of the Hive Cities, in the catacombs and tunnels and hollowed out caves within the very foundations of the city, and the barren wastes that often surround the major Hive structures, are home to the most destitute, for whom life is a moment-to-moment struggle. This is a sprawling slum inhabited by hideous mutants, grotesque abhumans, terrible disease, some of the worst criminal scum in the galaxy, and Heretics. Abject poverty is the norm, and even the most successful will barely scrape by. The Arbites will rarely venture to these places, so they tend to be lawless and incredibly dangerous. Daily life for someone here is a brutal test of survivability, punctuated by malnutrition, injury, and disease.

Where you start to see "normal" people is in the lower class, in the industrial sectors and forges. This is where the majority of a Hive City's population resides, and is mostly made up of manual laborers. Here, it is a work-till-you-die arrangement for most. Many will be equivalent to slaves, but are rarely starving. They often live where they work, and get virtually nothing in the way of "leisure". They are forced to breathe the polluted air, work in overall terrible conditions, and death is common. Most will live and die within the walls of their sector, never having seen the sun or felt a breeze. 

What some call the "Upper Hive" is basically your "middle class". A vast plethora of bureaucrats, administrators, politicians, traders, and skilled professions. These people will work hard, but will have time for leisure, will live relatively comfortably in the aggregate, and will feel generally safe. They may rarely venture into lower levels.

Within the Hive's Spires, projecting miles into the sky, high above the pollution and the clouds, reside the upper echelons of Imperial culture. Life will be incredibly comfortable for these people. While they technically oversee a majority of the City's functioning, or its interactions with the wider Imperium, they will have dozens of aides and subordinates to do most of the work. Life is probably like the ancient depictions of Kings and Queens, when Holy Terra was still known as Earth. 

Within the Tau, on the other hand, the social strata is much more evenly distributed in general. They utilize a caste system that places the needs of the many above the needs of the few. Even your lowest ranking individuals will live relatively comfortably. They understand that a healthy populace yields greater overall results for the species as a whole. Even laborers and low ranking soldiers will be treated relatively well and will be pretty well taken care of. Daily life here is largely dependent upon your position within your caste, but in the aggregate you will still have time to actually "live a life", as it were.