The 64 hexagrams of the I Ching are associated with specific dates in the Chinese calendar. So, in certain readings, the dates connected to the response hexagrams could be the most important information obtained from casting the change.
Four of the hexagrams cover a 3 month period and the rest apply to 5 or 6 days of the lunar year depending on the month, since some have 29 days and others have 30.
Each year at Chinese New Year, I prepare my I Ching calendar so that I know which hexagrams aplly to which days. I've gotten feedback from clients telling me that the dates I gave them when I interpreted their changes for them were right on. In some cases, you can phrase your query so as to ask the "when" question and get an answer about the timing of the next changes in a specific domain. I could post the master chart online if there is interest.