Thanks to the ongoing interest in private letters as sources for reconstructing language variation and change in the past, epistolary formulae have attracted increasing attention cross-linguistically. Studies showing that low-status writers and women relied heavily on formulae when writing their letters have hypothesised that formulae served primarily as aids for little experienced writers. However, other studies have shown that formulae could perform different functions related to group practices and self-representation. I investigate this issue in the context of sixteenth-century Florence, where letter-writing was becoming increasingly codified. Drawing on little-known archival material and focusing on the epistolary closing, I track the use of formulae across the private letters of three women from subsequent generations of one family, the Ricasoli, and compare it to the use of their brothers. These three women differed markedly in their degree of writing experience, in keeping with the increase in female literacy that was affecting the Florentine patriciate. The results show that the woman of the last generation used more formulae, that a writer’s use of formulae throughout their lifetime did not necessarily decrease with an increase in writing experience, and that it was not always the case that women used more formulae than men. This suggests that, in Renaissance Florence, optional epistolary formulae played a role as social conventions and not only, or primarily, as formulation aids for little experienced writers.