Basically, Calamari provides 2 accrual options: 'estimate future entitlement' and 'calculate as of current day' .
Estimate future entitlement
This option allows employees to plan future absences, and the system calculate the available day in favour of employees. For example, if your absence type accrues 2 days per month and you run out of your entitlement, you will be able to request a leave for future months even now. This is because the Calamari system knows that employee will receive future entitlement.
Calculate as of current day
This option calculates the entitlement in a slightly different way. It allows you to take only the earned days. In comparison to 'estimate future entitlement', this option doesn't calculate future accruals - if you run out of your days, you simply can't take more, even for months ahead. An employee will be allowed to request days in the future based on the entitlement already earned.