From each according to his ability, to each according to his need
Who decides what your ability or need is? It would take some sort of position of power to determine who is in need and who has ability. I am in the belief that power naturally corrupts and tends to find ways to increase and consolidate power. After time, you are left with those who have consolidated power to abuse, and those who don't.
The slogan you quote is to be taken to indicate free access to products and means to produce more products.
As such, this mode of production, characerized by the immediate appropriation of conditions of labour (getting rid of capital as a mediating instance) and the products of labour is a tendency of a socialist/communist society in so far as it rests upon the advance, the increase in labour productivity (meaning instead of 3 Xs per hour of labour, we get 6 Xs) which is enabled by technological gains and the reorganization of production.
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“The possibility of securing for every member of society, by means of socialized production, an existence not only fully sufficient materially, and becoming day by day more full, but an existence guaranteeing to all the free development and exercise of their physical and mental faculties – this possibility is now for the first time here, but it is here.” Friedrich Engels
"The proletariat is its struggle; and its struggles have to this day not led it beyond class society, but deeper into it." Friends of the Classless Society
"Your life is survived by your deeds" - Steve von Till