used when constructing mock galaxy catalogs or for consistently fitting clustering measurements at different epochs.

Finally, in [@Zehavi:2017] (hereafter Z18) we use SAMs to investigate how the galaxy content of dark matter haloes is influenced by the large-scale environment and halo age at $z=0$, for galaxy samples selected by their stellar mass, finding distinct variations of the halo occupation functions. We show that haloes which form early have more massive central galaxies, and thus start hosting them at lower halo mass, and fewer satellite galaxies, compared to late-forming haloes. We also find similar results in hydrodynamical simulations [@Artale:2018]. These [*occupancy variations*]{}, namely the dependence of the HOD on halo properties other than mass, are intimately related to assembly bias, as it is their effect combined with [*halo*]{} assembly bias that gives rise to [*galaxy*]{} assembly bias.

Here, we build on our previous studies and investigate the evolution of assembly bias and specifically the occupancy variations in SAMs. We extend the analysis of Z18 in a number of ways: 1) we study a wide range of redshifts between $z=0$ and $z=3$; 2) we explicitly examine separately the different manifestations of assembly bias, namely halo assembly bias, occupancy variation, and galaxy assembly 