  We use the 30 simulations of the Auriga Project to estimate the temporal
dependency of the inflow, outflow and net accretion rates onto the discs of
Milky Way-like galaxies. The net accretion rates are found to be similar for
all galaxies at early times, increasing rapidly up to $\sim 10~\mathrm{M}_\odot
\, \mathrm{yr}^{-1}$. After $\sim 6~\mathrm{Gyr}$ of evolution, however, the
net accretion rates are diverse: in most galaxies, these exhibit an
exponential-like decay, but some systems instead present increasing or
approximately constant levels up to the present time. An exponential fit to the
net accretion rates averaged over the MW analogues yields typical decay
time-scale of $7.2~\mathrm{Gyr}$. The analysis of the time-evolution of the
inflow and outflow rates, and their relation to the star formation rate (SFR)
in the discs, confirms the close connection between these quantities. First,
the inflow$/$outflow ratio stays approximately constant, with typical values of
$\dot{M}_\mathrm{out}/ \dot{M}_\mathrm{in} \sim 0.75$, indicating that the gas
mass involved in outflows is of the order of 25% lower compared to that
involved in inflows. A similar behaviour is found for the SFR$/$inflow rate
ratio, with typical values between 0.1 and 0.3, and for the outflow rate$/$SFR
which varies in the range $3.5$--$5.5$. Our results show that continuous inflow
is key to the SFR levels in disc galaxies, and that the star formation activity
and the subsequent feedback in the discs is able to produce mass-loaded galaxy
winds in the disc-halo interface.
