Research on task repetition (TR) has consistently showed beneficial effects for L2 oral production in terms of CAF measures (complexity, accuracy, and fluency). However, open questions exist regarding the modality-dependency and proficiency-dependency of TR learning affordances. To advance research in these two areas, the study reported in this chapter investigated TR across modalities and L2 proficiency levels. The participants were 29 (16 high-school and 13 university) Spanish EFL learners who completed a decision-making task twice, either orally or in writing. Their task performance was assessed in terms of CAF measures using a wide range of indices. Results confirm some of the previous predictions regarding the modality-dependency of TR effects, and additional modality-related effects were also found. These findings shed light on the greater language learning affordances of writing as compared to those created by speaking tasks.