I just bought a Samsung Note 2. My mom uses it when we are in India, but I use it when we are in the U.S. Is there a way to have two separate accounts so that our apps don't get mixed up? I'd like to have a completely separate set of app pages and saved data (eg. so I can have a different WhatsApp account on the same device than my mom).
There are a few options available, but the effective ones I came up with will require root access. And the second option may require an unlocked bootloader (I'm not sure if the Note 2 can unlock its bootloader or not).
Even if you have the most recent version of Android, Google has not enabled multiple users for phones; they figure people share tablets, but have their own phone. And there are some issues that come with multiple users on a phone.
Specific app profiles (root required)
There are apps such as Titanium Backup that let you create profiles for apps, and it works on any version of Android. You select the apps that you want to be multi-user. Then you add a widget to your homescreen that lets you choose which user you want to switch to. Titanium Backup will then back up the data for the current user and restore the backup data for the user you select.
If you're worried about one user getting text messages, you'll either have to insert a different SIM for each user (and thus change the phone to a new number), or set up each person with a Google Voice number. Then, have the Google Voice app be set up with multiple profiles.
Full Nandroid backup/restore - most effective (root required)
If you root it and install a custom recovery, such as ClockWorkMod (cwm) or TWRP, it would be a very simple process. Just do a full backup of the phone, then do a factory reset. Give the phone to your Mom, and she can set it up like her own phone.
Once she gives the phone back to you, do a full nandroid backup again in the recovery, then recover your own image. This will clear all her data (except anything stored on the SD card, such as images and other files) and restore your own. After you boot up the phone, it will be like she never touched it.
Yes. In Android Lollipop it is possible to have multiple separate user accounts with separate apps and app data. So your apps and its data won't be mixed up. If you don't want to switch or couldn't update to Lollipop then you can use apps such as tasker or Nandroid backups as Stephen suggested.
Read more on Multiple User Accounts in Lollipop.