IT may have become a common practice in China for monthly mobile Internet data that hasn’t been used to simply disappear at the end of the month. But things started to change on Oct 1 with the start of rollover (顺延) data services. Users of the top major telecom companies – China Mobile, China Unicom, and China Telecom – can now use the data that is left over in the next month. But if it is still not used up in the second month, it will be cleared.