Time period to check the data usage depends from user to user. It also depends upon the invoice date at which the data usage ends and the bill is sent to the user. In Android 6.x Marshmallow, it is 1-month period, i.e. 30 or 31-day period. But, you may set any date of starting the data usage. If you are using the metered connection of data usage, you may start any date, depending your requirements.
It is easier to set the date and period, as per your need and requirements but if you need any help, feel free to see the instructions.
Instructions
Command Line: Settings Button – Home > Settings Screen > Data Usage > Data Usage Screen > Data Usage Switch On > Change Popup > Change Cycle > Usage Cycle Reset Date > Set Button
1: Tap the icon of the ‘Settings’ app at the bottom-right corner of the Home screen of your Android Marshmallow smartphone or tablet to open up the ‘Settings’ screen.
2: At the ‘Settings’ screen, tap the ‘Data usage’ in the ‘Wireless & networks’ section.
3: At the ‘Data usage’ screen, see; the ‘Cellular data’ switch is not set to ‘On’, i.e. cellular data is not activated. Tap it to activate it.
4: Now, when the ‘Cellular data’ is activated, tap the popup button, placed at the right of the period. It will open up a popup menu.
5: In the popup menu, tap the ‘Change cycle’. It will take you to a prompt, named; ‘Usage cycle reset date’ with a slider to change the date.
6: Here, at the slider, scroll up or down to change the date, as per your requirements.
7: After setting the required date, tap the ‘SET’ button to save the change. It will take you back to the ‘Data usage’ screen. See here, the period has been changed, i.e. it will display the changed data level.
That’s all!