Why don't you offer credits for missed lessons?
The overhead costs of caring for the horses are extremely high, and don't change when students have to miss a lesson. The horses' costs are the same each month regardless of whether students attend every lesson.
On average, we have one student per day has to cancel their lesson. If every one of those students were given credits towards their tuition the following month, we would not earn enough to cover the costs of the horses.
To earn consistent revenue to maintain the horses, we use a monthly tuition payment system and offer makeups for missed lessons. The tuition price is the same regardless of whether there are 4 or 5 weeks in a month, and students have 60 days to makeup missed lessons.
Many riding schools don't offer makeups and charge a cancelation fee. With our system, we are able accommodate "last minute scenarios", such as kids getting sick the day of their lesson.