You do need to refrigerate your cheesecake once it is made. Due to all the dairy in the cheesecake, it will spoil if left out at room temperature. A good rule of thumb is to never allow your cheesecake to be set out for more than 2 hours at a time or bacteria can begin to grow at a more rapid pace. Refrigerate for at least 30 minutes before pulling the cheesecake out to serve again if it was out for 2 hours.