This paper makes the case for close and approximate replications of Erlam (2005) and a conceptual replication of Roehr-Brackin and Tellier (2019). The two studies recommended for replication are informed by research on explicit and implicit knowledge, learning and teaching. They are ecologically valid classroom studies with either adolescent or child learners as participants and thus investigated as yet relatively under-represented populations in the field of instructed second language acquisition (SLA). Erlam (2005) identified a levelling effect of a particular method of explicit instruction, while Roehr-Brackin and Tellier (2019) showed that language-analytic ability has a role to play even in younger children's language learning. The researchers' approaches duly reflect the need to take into account cognitive individual learner differences when working in intact classrooms. As the findings of each of the original studies have potentially profound implications for theory and practice in the field, replication is deemed both timely and desirable. In order to facilitate this endeavour, the key features of the original studies are summarised, and specific proposals on the methodological characteristics of suitable replication studies are put forward.