This paper raises the metatheoretical question of whether readjustment (i.e. the alteration of stem or affix phonology after lexical insertion) is needed for morphological theory. Domains investigated include: (i) the employment of readjustment rules as “secondary exponence” in Distributed Morphology; (ii) verb stem allomorphy in the Uto-Aztecan languages Hiaki (Yaqui) and Classical Nahuatl; and (iii) verb stem allomorphy concurrent with reduplication in the Oceanic language Sye (Erromangan). A cogent argument in favor of readjustment rules over stem-listing approaches invokes frequent phonological regularity of stem alternants (e.g., Harley and Tubino Blanco’s 2013 analysis of stem form alternations Hiaki). I adopt an alternative, “amphichronic” (Kiparsky 2006) approach whereby such regularities can be just as felicitously explained by appealing to historical linguistic processes.