  In this letter, we explore the quiescent lives of central galaxies using the
SAGE galaxy model and Uchuu dark matter simulation. We ask three questions: (1)
How much of a galaxy's life is spent in quiescence? (2) How often do galaxies
transition off the main sequence? (3) What is the typical duration of a
quiescent phase? We find low and high-mass galaxies spend the highest fraction
of their lives in quiescence: 45 \pm 19% for log10(Mstar) < 9.0 (3.68 \pm 1.80
Gyr) and 26 \pm 25% for log10(Mstar) > 11.5 (3.46 \pm 3.30 Gyr), falling to 7
\pm 13% for galaxies in-between (0.82 \pm 1.57 Gyr). Low mass galaxies move in
and out of quiescence frequently, 2.8 \pm 1.3 times on average, though only for
short periods, 1.49 \pm 1.04 Gyr. This can be traced to the influence of
supernova feedback on their quite stochastic evolution. Galaxies of higher mass
have fewer quiescent periods, ~0.7 \pm 0.9, and their length increases with
mass, peaking at 1.97 \pm 2.27 Gyr. However, our high-mass population comprises
star-forming and quiescent galaxies with diverging evolutionary paths, so the
actual time may be even longer. These high-mass trends are driven by radio mode
feedback from supermassive black holes, which, once active, tend to remain
active for extended periods.
