A general requirement of cloud microphysics modeling at any scale is to represent the number, projected area, and mass size distribution of hydrometeors. Here we focus on simulation of observed size distributions of precipitating hydrometeors, i.e., those of roughly 50 micrometers or greater maximum dimension. The first half of the presentation will focus on observational evidence of near-equilibrium raindrop size distributions in the tropics. The observed size distributions are compared with laboratory and theoretical results and with parcel and 3D simulations using size-resolved and two-moment microphysics parameterizations. The second half of the presentation will focus on the link between precipitating ice size distribution shapes and ice single-particle properties, which vary substantially with environmental conditions.