At one time, I found it useful to think in terms of Marx’s dictum: from each according to their abilities, to each according to their needs.
Start with Plato, not altogether literally. Society gets the sum and the distribution of abilities to operate their social technology, but individual abilities (who gets to do what) are distributed randomly (nature rolls the dice). So, there is the productive sector, the social sector, the defence sector, and the political sector. People are allocated to these sectors according to their abilities. Importantly, there is no entertainment sector: poetry, music, theatre – those just introduce hedonistic needs, which at best contribute nothing to the abilities, and may in fact be detrimental to their adequate exercise.
There is no discrimination on any ground (race, gender, birth, or whatever). Needs are determined by social roles, which determine the distribution of resources and incomes. E.g. those in the military own weapons, live in common quarters, and eat more than others; producers own land, capital, and houses they live in; philosophers and others working in the political sector live modestly and own nothing; people working in the social sector own their houses or apartments, but not the facilities they work in, and have a diet that allows them to maintain their abilities.
So, wealth and income are distributed so that social roles can be fulfilled. There is no surplus beyond temporary inventories to insure against risks; those are zero over time. Nobody maximises anything (certainly not utility, which is why entertainment is perhaps to be allowed when it cannot affect the senses, i.e. at old age, in retirement).
The society or polity is self-sufficient; it is a cosmopolis – there is no trade with the outside world, except for occasional wars with barbarian states which do not operate under Marx’s dictum. There is paper money, which is purely a veil (it is basically a book keeping device). There are no banks.
This is egalitarian in the sense of being just: equals are treated equally (horizontal justice) and the unequal, unequally (vertical justice). More than that: everybody contributes equally in terms of doing the best they can and everybody’s needs are satisfied equally in the sense that all their needs are covered. Equality of rewards, satisfaction, utility, income, wealth or whatever else plays no role whatsoever.
Now, Marx, following Descartes basically, again not literally, assumed that everybody was equal in their non-physical abilities (res cogitans). Marx’s actual formulation admittedly needs a bit of interpretation:
“In communist society, where nobody has one exclusive sphere of activity but each can become accomplished in any branch he wishes, society regulates the general production and thus makes it possible for me to do one thing today and another tomorrow, to hunt in the morning, fish in the afternoon, rear cattle in the evening, criticise after dinner, whatever is to my liking, without ever becoming hunter, fisherman, herdsman or critic.”
So, once e.g. robots take over all the physical tasks (res extensa), sectoral specialization disappears, division of labour also, and the differences in the physical and non-physical needs too.
Robots contribute according to their abilities, and maintain themselves according to their needs.