No two arcologies are quite same, not even the NESTs which are semi-standardized. Any building project is going to need to acquiesce to the demands of the environment its built in, and megastrucutres all the more so. However, it can be safely said that any given area of an arco embodies a certain ethic about the role of the home and family.
In the low income areas of a NEST, the standard is "Life is outside the home". Individual apartments are often only four to six hundred square feet, with some beds, closets, a counter with sink and induction stove top, and a tiny bathroom. Most occupants are expected to remain within for a few hours to sleep, and to store their belongings. Otherwise they can expect to socialize in the hundreds of stores, cafes, bars, arcades and parks within the structure. Maintenance staff and police would be very concerned if someone remained in their apartment for an extended period.
Apartments with windows are actually fairly rare. Usually the outer area is reserved as walkways and parkways - with sunlight access for everyone, even on mostly residential floors there are communal dining areas and entertainment parlors. On many levels, there are even plants, landscaping, and grass fed by drip hydroponics to give the appearance of a park wrapping around the entire building. Living areas are set up in blocks of 20-40 grouped together. If one could look through the ceiling and outer structural elements, any given level would look quite a bit like a normal city block, just sectioned off at a three meter level. Hallways are kept quite wide - usually about five meters (14 feet) for ease of access, and to account for people standing outside and talking. Lighting in hallways is dimmed for night time, but does have constant signs. Large doors can be found every few hundred feet and in an emergency the various levels can be locked down tighter than a prison to contain fires, riots, or other problems.
Despite the tiny and seemingly temporary nature of the apartments, they are designed to be very livable, rather than depressing little boxes. Even those in the inner core of the building can receive natural light through fiber-optic "sun tubes". Programmable strips lights are built into the walls at floor, chest, head, and ceiling levels to let the users customize exactly what level of illumination they desire at any given moment. Floors are usually bamboo-hardwood for ease of cleaning and a calming natural appearance - though the occupant can request different coverings. Projectors or screens are often built in to allow entire walls to be used for as a television or monitor.
A great deal of effort has been made to insulate the apartments - both due to the noise of so many things going on in a large building, and efficiency standards. Despite the normal connotations of block housing, sharing walls is often rather rare, as there are a great deal of passage ways between the various living areas. Part of this is structural - each tier is a bit offset to allow structural members through and the massive reinforcement needed for structures over twice as tall as any 20th century building. The other reason is the need for maintenance access for all the electrical tech - and to allow emergency services non-standard ways to move through a crowded building in an emergency. It is actually possible to traverse the entire building without seeing another person even at peak occupancy if one has the right key-cards.
More affluent areas of the NEST (ie Lower Down) are of course, notably larger. They are still not large penthouses, but something that separates the sleeping area from the dining room, or has an actual office in addition to the standard area is worth bragging about. Decoration is often more lavish as well.
Conversely, communities like the Lone Star Complex believe that the home is the center of one's social life. Although the bedroom and kitchen areas are often tiny - open floor plans lead to huge dining and living rooms so that many friends may gather to share food and entertainment. Multiple couches are such a part of this mindset that doors are specifically made wider than the long time 3 foot/90cm standard to ease moving them in. Although there are still nearby blocks of commercial areas, the overall effect is less metropolitan. Much the same lighting and sound amenities are present, but the larger space makes them more of a way to accent the space then a requirement tot make the tiny areas livable.
There are places that take both these elements to other levels. In the underground city of Tesla, most people store what they cant carry in banks and only use coffin like areas for sleeping. Meanwhile, other arcos are designed around traditional homes, but built in rounded or half buried forms for efficiency.
Places that are not arcologies are usually quite similar to 20th century apartments. The big difference is that most are adapted for new technology and living standards. Almost every surface is fitted with induction charging pads so one needs to simply set down a device and it powers up. Even closets contain power supplies as many garments incorporate semi-flexible wearable computers.
The use of electricity is heavily encouraged in future living. natural gas or oil are limited resources, and require special means to pipe them around. Electricity can be produced two thousand kilometers away by the tides or on the roof by the sun and works just the same. Water however, is quite often rationed or highly expensive due to the difficulties of piping and supply.