The question of whether full-day pre-kindergarten benefits students naturally rests upon understanding how the additional time in school is used, relative to how it would have been used in the absence of the full-day option. We therefore also present evidence gathered from parents and teachers via surveys about time-usage both inside and outside of formal pre-k time. This allows us to describe implementation fidelity, investigate heterogeneity across sites, and explore the mechanisms through which the additional time may be leveraged.