Taking a test on material that has not yet been studied can improve long-term retention of the material even when the initial guess is wrong. In the present study, we used weakly associated word pairs (Experiments 1 and 3), Swahili–German word pairs (Experiment 2), and prose passages (Experiment 4) as study material to examine whether this pretesting effect is modulated in magnitude when pretests are repeatedly administered during learning. Results of Experiments 1-4 consistently showed the typical pretesting effect, with improved recall performance after a single guessing attempt relative to the study-only baseline. Critically, the pretesting effect increased in size when multiple guessing attempts were made during learning, regardless of whether the duration of the pretesting phase increased with the number of guesses (Experiments 1, 2, and 4) or was held constant (Experiment 3). Taken together, the results show that additional guessing can promote access to the pretested material on the final test and suggest that in educational contexts, extensive pretesting during acquisition can serve as an effective learning strategy.