I want to lend my phone to my bro. How to save data that I can restore some other times?
I have used an iTunes backup to restore my phone on more than one occasion. I personally prefer an iTunes backup over iCloud for many reasons. The time required to complete a backup is significantly reduced with a wired connection. With iTunes you have the ability to backup any apps .ipa files. This is useful if you've ever updated an app you love and then immediately regretted the update. 

Be aware that when you backup your data with iTunes, by default every time you backup your data it overwrites the old backup with the new one.  This is not always such a good thing but you can overcome this easily with the following steps. 


Open iTunes and click Preferences in the menu bar 
Once inside Preferences click on the section labeled devices.


In the Devices section you will find a list of backups for your device. 
Right click on any backup listed and you should then see an option to Archive. 
Select Archive for any backup you want to keep. This will prevent it from being overwritten the next time you back up your device and from any future backups. 



If nothing is listed in the Devices section of Preferences, that means you don't have any saved backups for your device in iTunes and might want to go ahead and do that.

Hope this helps.