Retrieval practice, or taking tests after studying, is a highly effective strategy to enhance learning. Furthermore, pretesting, which involves attempting and failing to guess unknown information before studying it, has emerged as a more effective strategy than mere re-studying. These methods exemplify errorful learning and represent powerful learning tools. In a series of experiments, we investigated how test order – whether administered before (pretest) or after (post-test) exposure to the learning material – affects memory compared to errorless copying (Experiment 1). Experiment 2 followed a similar design but included a copy-test-copy condition to further explore the potential impacts of test order. The results revealed that the pretest, post-test, and copy-test-copy groups all improved memory compared to errorless copying, with no difference between the three. Error type analysis indicated minimal intrusion errors. In Experiment 3, we explored the pretesting effect in older adults. The results showed that pretesting significantly enhanced memory compared to copying, indicating the robustness of pretesting in healthy aging and across age groups. Interestingly, participants across the experiments consistently underestimated the efficacy of testing, revealing a gap in metacognitive awareness. These findings underscore the efficacy of errorful learning as a robust strategy with broad applicability across diverse populations and procedures.