Tuition is charged by the semester and covers typically 10 lessons over a 12 week period. In the event you cannot make it to a lesson for any reason, the extra 2 lessons a semester are to be used as make-ups. More than these 2 make-ups may be offered only in case of family emergency or extreme illness. The tuition per semester is calculated by adding the price of 10 individual lessons, so you are essentially getting two lessons for free if you are able to attend all 12!
As an active performer, my schedule can change. I usually know of these changes a few weeks in advance, and if we need to reschedule because of me, I will not count that as one of your make-ups.