No. There is no need to backup your data. All of your data is stored securely on our servers. These servers are backed up every hour.
You do need to remember what you used to create an account with originally. This is just like Instagram or Snapchat.
If you're getting a new phone or tablet/iPad, just login with your email and password and your data will be there.
You can also login to multiple devices. Have an iPad/Tablet login to both.