  The thermal radio emission of novae during outburst enables us to derive
fundamental quantities such as the ejected mass, kinetic energy, and density
profile of the ejecta. Recent observations with newly-upgraded facilities such
as the VLA and e-MERLIN are just beginning to reveal the incredibly complex
processes of mass ejection in novae (ejections appear to often proceed in
multiple phases and over prolonged timescales). Symbiotic stars can also
exhibit outbursts, which are sometimes accompanied by the expulsion of material
in jets. However, unlike novae, the long-term thermal radio emission of
symbiotics originates in the wind of the giant secondary star, which is
irradiated by the hot white dwarf. The effect of the white dwarf on the giant's
wind is strongly time variable, and the physical mechanism driving these
variations remains a mystery (possibilities include accretion instabilities and
time-variable nuclear burning on the white dwarf's surface).
  The exquisite sensitivity of SKA1 will enable us to survey novae throughout
the Galaxy, unveiling statistically complete populations. With SKA2 it will be
possible to carry out similar studies in the Magellanic Clouds. This will
enable high-quality tests of the theory behind accretion and mass loss from
accreting white dwarfs, with significant implications for determining their
possible role as Type Ia supernova progenitors. Observations with SKA1-MID in
particular, over a broad range of frequencies, but with emphasis on the higher
frequencies, will provide an unparalleled view of the physical processes
driving mass ejection and resulting in the diversity of novae, whilst also
determining the accretion processes and rates in symbiotic stars.
