Distribution of the fractional main sequence lifetime spent in the Case A mass transfer phase (τ_Case A/τ_MS; see text for the exact definition) of models with τ_Case A/τ_MS > 0.001. The colour coding differentiates between models arising from different ranges of initial orbital periods. The star hatching in each fractional main sequence lifetime bin denotes the relative number fraction of models in that bin that go through a contact phase during Case A mass transfer.