How many times can you renew a library book/textbook that isn't on reserve?
As long as another student hasn't requested the book, you can continue to renew it until the end of the semester. All items are due no later than the end of the semester.
If someone does put in a request for the item, you will need to return it by its due date. You can always sign in to your library account to see the due dates for your checked-out items.