Availability
Availability is when a person can and cannot work. It covers the hard cases — the afternoons they are in class, a date they are away — and the softer question of which of the shifts on offer they would rather have.
Why it matters in a small workplace
A week built without it is a week built from memory, and the corrections arrive after it has been published. Collected before the week is drawn, it is the cheapest information a schedule ever gets.
How Weeksort handles it
Weeksort keeps the two apart. Unavailability is hard — recurring by weekday or on a single date — and it makes somebody ineligible. Preferences are five rungs, from want a lot to cannot, filed on the shifts a person is eligible for while the week is open.