There is now substantial evidence that the progenitors of some core-collapse supernovae undergo enhanced or extreme mass loss prior to explosion. The imprint of this mass loss is observed in the spectra and dynamics of the expanding blast wave on timescales of days to years after core collapse, and the effects on the spectral and dynamical evolution may linger long after the supernova has evolved into the remnant stage. I will present recent results which highlight how mass loss, either isotropic or enhanced during some late stage of the progenitor's evolution, can profoundly impact the dynamics and spectral qualities of the supernova remnant, centuries after core collapse.