The concept of ‘renewal’ is widely used in the literature on morphosyntactic change, but hardly ever theorized. Here we scrutinize the viability of this concept theoretically as well as empirically, revisiting in detail the most frequently cited case of renewal, namely the resemblance between the Latin and French synthetic futures. Phenomena accounted for in terms of renewal can also be accounted for in terms of grammaticalization theory. We argue that there is no need and no empirical support for renewal as its own type of change alongside grammaticalization. However, grammaticalization theory so far has neglected to properly account for influences of the existing system on ongoing grammaticalization processes. As an initial approximation of this vast field of study, we propose several domains where we believe that system influences on grammaticalization are operative. On the one hand, this involves making more precise the source determination hypothesis as developed in work by Joan Bybee and colleagues. On the other, it comprises interactions between constructions in paradigm formation.