How to change due dates for the upcoming year (do this at the very end of a school year, or at the very beginning before checkouts start)
How to move students into their correct homerooms (do this at the beginning of the year, at least one day before you start checking out books, most important for elementary).
How to clean up your patron records and delete graduating/inactive students (any time of year but usually the start of the new school year)
How to do Global Renew for teacher Chromebooks/Textbooks (do at the end of the school year but before you give teachers a list of what's due back from them)