I seem to recall reading that under EU law a bond has to reduce linearly and can not be for more than one year.
Flying instruction is not an easy job if you are going to do it well. Some times I enjoyed it, others not so much, especially with students who came unprepared for the lesson and 6 hours of trial flights in one day could be tedious especially when the customer was not really interested in what was just a Christmas gift.
Some people are naturally good at teaching, others not so which is perhaps why I found it could be hard work at times. However it did teach me a lot of valuable lessons.