  Using a hybrid binary population synthesis approach, we modelled the
formation and evolution of populations of accreting WDs for differing star
formation histories. We found that the delay time distribution of SNe Ia in the
single degenerate scenario is inconsistent with observations. Additionally, we
found that our predicted X-ray and UV emission of populations of accreting WDs
are consistent with the X-ray luminosities of early-type galaxies observed by
Chandra and the HeII 4686\AA/H\beta line ratio measured in stacked SDSS spectra
of passively evolving galaxies. Moreover, we found that the majority of current
novae in elliptical-like galaxies have low-mass WDs, long decay times, long
recurrence periods and are relatively faint. In contrast, the majority of
current novae in spiral-like galaxies have massive WDs, short decay times,
short recurrence periods and are relatively bright. Our predicted distribution
of mass-loss timescales in an M31-like galaxy is consistent with observations
for Andromeda.
