  Radial velocity (RV) detection of planets is hampered by astrophysical
processes on the surfaces of stars that induce a stochastic signal, or
"jitter", which can drown out or even mimic planetary signals. Here, we
empirically and carefully measure the RV jitter of more than 600 stars from the
California Planet Search (CPS) sample on a star-by-star basis. As part of this
process we explore the activity-RV correlation of stellar cycles and include
appendices listing every ostensibly companion-induced signal we removed and
every activity cycle we noted. We then use precise stellar properties from
Brewer et al. (2017) to separate the sample into bins of stellar mass and
examine trends with activity and with evolutionary state. We find RV jitter
tracks stellar evolution and that in general, stars evolve through different
stages of RV jitter: the jitter in younger stars is driven by magnetic
activity, while the jitter in older stars is convectively-driven and dominated
by granulation and oscillations. We identify the "jitter minimum" -- where
activity-driven and convectively-driven jitter have similar amplitudes -- for
stars between 0.7 and 1.7 $M_{\odot}$ and find that more massive stars reach
this jitter minimum later in their lifetime, in the subgiant or even giant
phases. Finally, we comment on how these results can inform future radial
velocity efforts, from prioritization of follow-up targets from transit surveys
like TESS to target selection of future RV surveys.
