Schedules should respect real working hours, not day-level guesses.
A five-day task is not always one calendar week. Weekends, holidays, and shift schedules change the true finish date. Without accurate calendars, schedules drift on paper.
Project-specific calendars define working days and hours.
Tasks can reference their own calendar when needed.
Calculations run at the hour level for accurate schedules.
You get dates that reflect how work actually happens — not how a generic calendar assumes it happens.