If you signed on to Google when you set up your phone, that backs up your Contacts and Calendar, if you sign in to G+ then your photos get backed up to Google+, if you have Verizon, they provide you with Verizon cloud which I use to back up SMS and MMS and Call logs, but it can also back up photos, documents, etc. but if you use more than the allocated space they give you then you need to pay for the service. You can also download ES File Explorer which lets you back up anything you want to any cloud service you may have.