The teachers program (BA) was officially 4 years long, meaning if one stays withing the minimum studying time, one needs at least 6 years. Like a med student, but with much less career development perspective, and a lower salary.
The different departments of each subject all have different system and some will need much more studying time to be finished compared to others in a completely unproportionate way.
The system changes every couple of years and student who work at the same time will find it difficult to keep up with changes and or find out some older exams have become obsolete.