Allocation Schedules are a mechanism whereby you can automate certain calculations at the start of each holiday period.
Within a schedule, you can predefine increases in an employee's base holiday allocation over the lifetime of their employment. Often employers will allocation additional holiday days to employees based on a number of years service.
You may also automate scenarios where employees are often allowed to "carry over" an amount of untaken holiday from one holiday year to the next or earn additional holiday based on a limited number of sickness days recorded in the previous year.
Allocation Schedules are used to define all of these. You can have as many allocation schedules as you like, and an employee can be assigned to any allocation schedule.