  Gravitational memory effects and the BMS freedoms exhibited at future null
infinity have recently been resolved and utilized in numerical relativity
simulations. With this, gravitational wave models and our understanding of the
fundamental nature of general relativity have been vastly improved. In this
paper, we review the history and intuition behind memory effects and BMS
symmetries, how they manifest in gravitational waves, and how controlling the
infinite number of BMS freedoms of numerical relativity simulations can
crucially improve the waveform models that are used by gravitational wave
detectors. We reiterate the fact that, with memory effects and BMS symmetries,
not only can these next-generation numerical waveforms be used to observe
never-before-seen physics, but they can also be used to test GR and learn new
astrophysical information about our universe.
