There are some circumstances that you want your smart phone be a non-smart phone. For example, you may forget to charge your phone last night, and you don’t have a charger in your office, and you suddenly find the battery is less than 20%. Or you are in outdoor travel, and the battery is low, but you don’t want to shutdown your phone because you want to keep in touch with others.

Turn your smart phone into non-smart then. It’s easy. For Android phone:

1. Turn off Location Access.
2. Turn off Wi-Fi.
3. Turn off Bluetooth.
4. Turn off Mobile data.
5. Adjust screen brightness as low as possible.
6. Open Notification Bar, tap Battery to view your battery usage, and force close all those apps that consume your battery more than your want. Uninstall bad apps if it’s essential.
7. (Optionally) Open Developer options, check Don't keep activities, and tap Background processes limit, and choose No background processes.
8. Press Power button once to close the screen and don’t frequently open the screen.