In general, items are returned within a few days of being due. The loan period for an item depends on the type of material, but for most items is 3 weeks.
Most materials will auto-renew, as long as no one else has a hold on the item. The best way to ensure the item is returned promptly and you get notified is to place a hold on it.
In addition to getting you in the queue for the item, placing a hold when you want an item also helps us know that there is demand! If something is particularly popular and has lots of holds we may buy additional copies.
And rest assured, we do follow up with patrons who keep items past their due dates. If a patron has an item more than 10 days overdue, they will be blocked from further borrowing until the item is returned.