Some learning schedules can foster an illusion of competence, whereby the learner feels that the skill will be retained better than it actually will be. Consider fixed-order practice, in which a person practices a task repeatedly before switching to the next task (e.g., task order A, A, B, B); in contrast, in random-order practice, a person randomly alternates among two or more tasks (e.g., task order C, D, D, C). In the present experiment, participants (n = 25) who had formal training in piano practiced melodies under fixed- or random-order conditions (within-subjects), and then returned for a retention test 2 days later. Initially, the participants performed faster on melodies practiced in a fixed-order. However, on a retention test 2 days later, participants were faster with melodies from the random-order condition. Despite the within-subjects design, which facilitated the comparison of practice conditions, participants' metacognitive judgments indicated an illusion of competence, whereby they erroneously believed that fixed-order practice would result in faster retention performance. Our results suggest that even some trained musicians may use ease of acquisition as a heuristic for predicting future performance.