Your items may stay in your room from the time your academic year contract begins (move-in) to the time your contract ends (move-out). This means you do not need to remove your items over any breaks between August and May. After your contract ends in May, you will need to move out your belongings and cannot keep them in the room over the summer even if you are returning to the same room in the fall.
To learn more about leaving over the break, check out this article.