Developer apps cydia launch release ReStats, This tweak works with iOS 8. ReStats jailbreak lets you to have your native cellular data statistics reset on a daily, weekly, or even a monthly basis. From tweak’s settings you can set it to reset stats on daily, weekly or monthly basis. For people who want to use this tweak specifically to know when they are about to run out of available bandwidth the monthly option is most suitable.
If you are interested, then you can free download ReStats iOS 8 from the BigBoss repository in Cydia. To install this program requires a jailbroken device (see if and how you can do the jailbreak to your iPhone by clicking here) and you need an Internet connection to download the package. This tweak is compatible with iOS 8.0 and later versions of the mobile operating system from Apple.