  Multiple approaches are required to study the evolution of black-hole
binaries. While the post-Newtonian approximation is sufficient to describe the
early inspiral (even from infinitely large orbital separation), only numerical
relativity can capture the full complexity of the dynamics near merger. We
combine multi-timescale post-Newtonian integrations with numerical-relativity
surrogate models, thus mapping the entire history of the binary from its
asymptotic configuration at past-time infinity to the post-merger remnant. This
approach naturally allows us to assess the impact of the precessional and
orbital phase on the properties - mass, spin, and kick - of the merger remnant.
These phases introduce a fundamental uncertainty when connecting the two
extrema of the binary evolution.
