Everyone has a goal when learning a foreign language whether it is for work, study or pleasure purposes. It is very important to estimate correctly how much time you can give to your lessons and be honest with yourself that you are serious about your learning.
My policy is clear: if a lesson is cancelled 24 hours or more before it is due to start then there is no charge. Less than 24 hours or simple absence of the student, then the lesson must be paid for.
I am sure you will agree that this is fair, both to keep the student motivated and serious about the lessons they have booked and to avoid wasting their teacher's time.....