This study investigated the perspectives of grade one and two teachers on the essential lesson preparation made and its usefulness in the teaching and learning process. Descriptive or transcendental phenomenology using semi-structured interviews collected data from 43 (18 first grade and 25-second grade) teachers sampled randomly among participants of in-service training programmes in Mufindi District Council and Mafinga Town Council in the Iringa region. Using thematic content analysis, the study established that teachers were aware of key preparation activities preceding a focused lesson. The lesson plan was their main activity for executing the selected learning activities using appropriate instructional strategies for equipping pupils with the desired learning competencies. Moreover, teachers prepared a lesson plan to guide and boost efficiency in terms of achieving lesson competency (ies), become confident; hence use for every lesson. The study concludes that most of the teachers supported the use of lesson plans to boost efficiency in teaching and learning and recommends that the production and distribution of the lesson plan be done by one unit/agency.