Medication deliveries from the pharmacy to nursing units should be frequent so medications are always available when they are needed. When deliveries are infrequent or unreliable, staff members may "borrow" medications from doses intended for other patients or may create stashes from discontinued medications. Both of these practices create an enormous opportunity for errors that can lead to adverse drug events. If the pharmacy dispenses a large supply of doses, e.g., enough for a 24-hour period, it introduces other opportunities for error, especially if the unit lacks a good system for immediately removing discontinued medications. Frequent delivery means the pharmacy must dispense fewer doses each time, and it can easily update the list of drugs to be delivered to fulfill the most current orders. Most important, the more frequent the deliveries, the fewer the opportunities for error.