The study investigates the interplay between task difficulty, learners' resources, and self-regulation, as described by Seufert's (2018) inverted U-shaped model. The model posits that self-regulated learning depends on task difficulty, learners' resources, and cognitive load. For easy tasks, resources are high and load is low, leading to no need for regulation. For difficult tasks, load is too high and resources are too low, also leading to no regulation. Only at moderate task difficulty do learners regulate, as resources and load are in equilibrium. The study uses a within-subjects design with 67 participants who reported on their cognitive and metacognitive strategy use for four exams of varying difficulty. Cognitive load and available resources (such as prior knowledge, interest) were assessed for each exam. Multilevel analysis revealed an inverted U-shaped relationship between task difficulty and the use of cognitive strategies, with increasing cognitive load mediating these relationships. For metacognitive strategies, only a linear relationship was found. The study also found a competitive mediation effect for learner resources, indicating that further mediators may be relevant. The findings support the validity of Seufert's model, suggesting that task difficulty, cognitive load, and learner resources interact to influence self-regulatory activities. The study provides insights into how these factors can be balanced to promote self-regulation in educational settings.The study investigates the interplay between task difficulty, learners' resources, and self-regulation, as described by Seufert's (2018) inverted U-shaped model. The model posits that self-regulated learning depends on task difficulty, learners' resources, and cognitive load. For easy tasks, resources are high and load is low, leading to no need for regulation. For difficult tasks, load is too high and resources are too low, also leading to no regulation. Only at moderate task difficulty do learners regulate, as resources and load are in equilibrium. The study uses a within-subjects design with 67 participants who reported on their cognitive and metacognitive strategy use for four exams of varying difficulty. Cognitive load and available resources (such as prior knowledge, interest) were assessed for each exam. Multilevel analysis revealed an inverted U-shaped relationship between task difficulty and the use of cognitive strategies, with increasing cognitive load mediating these relationships. For metacognitive strategies, only a linear relationship was found. The study also found a competitive mediation effect for learner resources, indicating that further mediators may be relevant. The findings support the validity of Seufert's model, suggesting that task difficulty, cognitive load, and learner resources interact to influence self-regulatory activities. The study provides insights into how these factors can be balanced to promote self-regulation in educational settings.