Each service takes as long as it takes for the individual to go through the checksheet at his own pace. The length of each service will also depend on how many hours one studies per week. On the average, Scientology training takes anywhere from a few days (for many introductory services) to several months (for more advanced training).
The Saint Hill Special Briefing Course, which is a chronological study of all materials of Dianetics and Scientology, takes approximately one year, at forty hours a week. This study gives the Scientologist the entire philosophic and technical development of the religion, and is the most extensive training course in Scientology.