Each data plan has data limit and expiration date limit. For example: 24GB-360days. This data plan has 24GB which can last for 360 days. If the 24GB data was used up before the 360 days expire date, the data plan will be expired. Or if the data has not been used up but the 360 days are up, the data plan will also be expired. It’s designed to give you ample flexibility with both a generous amount of data and plenty of time to use it?