Baković (2005) analyzes the avoidance of 'sufficiently similar' adjacent consonants as the interaction of independent antigemination and assimilation processes. We present evidence from the phonology of monoconsonantal proclitics in Polish in support of the primary consequence of this analysis, that any conditions on antigemination or assimilation will also be conditions on 'sufficient similarity' avoidance. These conditions concern the segmental contexts in which geminates are disallowed in Polish and the variability of one of the assimilation processes involved. The analysis is further corroborated by the coincidence of two changes in progress: as the rate of variable assimilation has gone down, so has the rate of 'sufficient similarity' avoidance.