SDI/TDI offer many specialty courses many of them help move toward not only becoming a better diver but also moving toward instructor. Spcialty courses should be designed around the student and we always recommend the most important ones first like the search and recovery as well as the deep cards.
Both assure a better quality of diving in the future as well as no restrictions on depth if you travel to other areas with the intent of diving. The advance diver assures this as well but its better to get a bit of training first. As we say blow some bubbles first!!!