Backing up your personal computer is a necessary precaution against data loss due to accidental damage, theft, or hardware failure. I recommend using an external USB 3.0 hard drive for this purpose (if you computer supports them), because they are so much faster. I would also suggest storing this hard drive in a separate location to your computer, or carrying it with you on your person, which will give you a simple "off site backup" solution.
According to the Back In Time homepage1:
"Back In Time is a simple backup tool for Linux inspired from "flyback project" and "TimeVault". The backup is done by taking snapshots of a specified set of directories."
While you can back-up any directories you please, I like to back up my home directory and keep all of the data I care about there.
On my Linux laptop running Fedora and Gnome, one command installs this application for me:
$ yum install backintime-gnome
Once it is installed, you will get the icon to run it on your application menu (run the non-root version for day-to-day usage).
The first thing you will need to do is choose the destination for your backups. Here I am choosing the USB hard drive I have connected:
You can optionally configure a backup schedule on this screen. Next, you must choose the directory to backup. I have chosen /home/john:
You can also choose to exclude some directories from the backup. Typically I exclude the Downloads directory from my backups and is tends to be too large, as well as containing files I can easily download again in the event of a failure.
Back In Time will make a snapshot backup of the selected directories when run. Each backup will only copy the files that have changed since the date of the last backup, and a full history of the changes is maintained by the application on the target hard drive. The thing I like the most about Back In Time is that the backups it creates are just standard files and directories, that can be navigated in the normally way.