A piano tuning business requires reasonable competence in dozens of tasks. The Registered Piano Technician exams test a cross-section of these competencies. Unfortunately, they test only nine basic tasks. Preparing for the RPT exams, you will perform better if you learn many more skills than what is minimally required.
The timeline below outlines one of many roadmaps to becoming an RPT in two years. If your goal is four years, double the times; and if three years, triple it, etc.