bias. This will enable the development of more sophisticated tests to search for assembly bias in the observable Universe. Our results will also help shape the design of new mock galaxy catalogues, which are necessary for the next generation of galaxy surveys.

The outline of this paper is as follows: in Section 2 we introduce the SAM used and describe the different galaxy and halo samples employed in this work. Section 3 shows our results regarding the evolution of halo assembly bias, while Section 4 presents our main results regarding the evolution of the occupancy variation. In Section 5 we study the impact of assembly bias on galaxy clustering and the evolution of galaxy assembly bias. Finally, in Section 6 we summarise our results and present our conclusions. We describe our publicly available occupancy variation measurements and parametric fits in the appendix. Throughout the paper masses are measured in $h^{-1}\, {\rm M_{\odot}}$, the SFR is measured in $\rm M_{\odot}/yr$ and distances are measured in $h^{-1}\, {\rm Mpc}$ and are in comoving units.

Theoretical background and sample definition {#Sec:GC}
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In this section we describe the dark matter simulation and the semi-analytic model used in this paper. We also present the 