Mass evolution of subhalos before and after infall (left and right of vertical gray line). The lines show the median evolution of ﹩{M}_{200{\rm{m}}}﹩ (blue) and ﹩{M}_{500{\rm{c}}}﹩ (orange) in their bound-only (solid) and all-particle (dashed) versions, including only epochs where the respective mass could be measured. Time is measured in units of the dynamical time at infall. All masses are normalized to ﹩{M}_{200{\rm{m}},\mathrm{bnd}}﹩ at infall, so that the solid blue line is unity at ﹩{t}_{\mathrm{infall}}﹩ by construction. Before infall, the all-particle and bound-only masses grow in unison and with modest scatter in their evolution. Just before infall, the all-particle masses sweep up additional mass from the future host, including roughly 40% more mass on average for ﹩{M}_{200{\rm{m}}}﹩ and about 10% for ﹩{M}_{500{\rm{c}}}﹩. After infall, the bound-only mass begins to decrease whereas the all-particle mass rapidly grows. However, around one dynamical (or crossing) time, the mass decreases again as the subhalos reach their apocenter.