When to use Days Off vs. Availability  

Days Off is a function that is used primarily for time limited periods of time when the employee isn’t working. (vacation, out of town, emergency, family reunion, etc.)

Availability settings also effect when a person is scheduled.  For example, you probably don’t want to make a habit of using the Days Off function for marking the person unavailable for Sundays.  You would want to use Availability settings that are more general and designed for that purpose.

Extended periods of time off

If someone has an extended leave of absence, you may not want to use Days Off for two month period such as Maternity Leave.  Alternatively, you can set the employee’s profile to Inactive from their profile page, and then turn them back to Active when they come back.  When they are inactive, you are not able to schedule them, even if just by accident, because they are pulled from the scheduler.

You can always restore them to active.