At my workplace there are certain skills that one needs and you can only get one particular skill by taking a course and/or challenging an exam. If you fail to pass the exam (pass grade is 80% btw), and you can only re-try it twice (so a total of 3 failures) then you become that much less versatile. For entry level staff this particular skill is quite key to a lot of their duties, so I can't imagine them having their term extended.