What is the reason why the memory of Apple 4s suddenly decreased overnight?

The IOS system itself also takes up a certain amount of memory, plus the applications you download, then 13.6G is normal.

1. Clear Safari cache

If you frequently use Safari to browse the web for too long, a lot of data will be cached. Only by clearing Safari's cache can it run smoothly. You need to go to (Settings) > (Safari), click "Clear History" and "Clear Cookies and Data".

2. Automatic updates and automatically downloaded content need to be turned off

If the iPhone is stuck when using it, it may be upgrading applications in the background. This step can be performed manually. To change the settings of automatic upgrade applications, go to (Safari) > (iTunes Store and App Store) > Automatically download items and turn them off all.

3. Unused photos and videos can be deleted

To speed up your phone, you need to delete some unnecessary files. If you have hundreds or thousands of photos or videos stored on your iPhone, you can back them up to your computer or other places. The memory space of mobile phones is limited, so mobile phones are really not a good place to store photos.

4. Delete software that takes up a lot of space

The larger the iPhone, the slower it runs. You can check the space occupied by each application in (Settings) > (General) > (Usage), and then delete those applications that take up a lot of space and are of no use. A large amount of software on a mobile phone will only slow down the running speed of the mobile phone.

5. Delete old text messages

A large number of text messages is also one of the reasons for slowing down the speed of mobile phones. Sometimes there are too many text messages, and when you open the messaging application, you have to wait for a while before you can enter it. . If you don’t know why your phone is stuck, you can try deleting useless text messages.

6. Close useless software running in the background

Although frequently closing the "background" will speed up the power consumption of the phone, for software that does not exist, close it and only keep commonly used software. That’s it. Music applications are resident in memory and are best closed when not in use.

7. Do not turn on the automatic mode if the operation can be performed manually

When the Apple phone performs any automatic operation, such as searching for nearby WiFi or upgrading applications, the running speed will be reduced. To turn off this feature, you need to go to (Settings) > (Wireless LAN) > (Ask whether to join the network), and then turn it off.

8. Restart your phone regularly

When using an Apple phone, most users will always keep it on, but it is actually necessary to restart their phone regularly. Turning off your phone can help your iPhone get rid of things that have been taking up system resources.

9. Upgrade and restore the system

The ultimate solution: Restore the system by flashing the machine and restore the system to its factory-fresh state.