[Diego Ceccacci]

Im planning to try wp10, so i need a backup in case i need to go back to 8.1.
How does it work?
What do you get back when use a backup? Everything? Only options?

[Wajeeh Maaz]

Go to Settings > Backup > Apps + settings, then turn on Settings backup and tap Back up now. And make sure you've enabled text backup. When you restore, this should restore your texts, OneDrive images,wallpaper(S), and download your apps

[ven07]

Should give you a fair idea :)

Backing up on Windows Phone 8.1 and other cool features you may not know about | Windows Central

[Diego Ceccacci]

So only apps and images? Doesnt it back up even the options i chose?

[ven07]

Please read the article :)

What exactly is backed up?

In case you were wondering what gets backed up, Microsoft has detailed it on their help and support site:

The apps you've installed on your phone, along with high scores and progress from participating apps.
The passwords for your accounts.
Your call history.
Your Start screen layout and theme color.
The accounts you've set up on your phone.
Your Internet Explorer favorites.
The custom words you've added to your phone's dictionary.
Settings from around your phone, including photos, messaging, email and accounts, lock screen, Speech preferences, and more.
In addition to the above, which is just for Apps + Settings, you can also optionally backup your text messages and photos/videos to OneDrive. Enabling all four settings will ensure a fairly robust restore to your new Windows Phone.