It is always recommended to log out of Facebook every time. It might have happened either to you or to your friend. You might have seen or heard of people leaving Facebook unattended. This may result in embarrassing comments, alteration of photos and more. In the worst cases, your personal info is used for nefarious purposes.
Logging out of the social network when not in use is the best way to prevent these pitfalls. Sometimes, you might accidentally forget to sign out of Facebook. There is a solution to this. Firefox web browser has an add-on called Facebook Auto-Logout. This will do the task for you.
1. Instal the Facebook Auto-Logout add-on.
2. It will be enabled by default. Whenever you close the Facebook window, it will log you out of the social network.
3. It will also log out after a minute of inactivity. If you feel this is too less then you can increase the auto-logout time. You can do this by clicking on the options next to the add on. Change the number in the box at the bottom.
That's all! This simple add-on can save you from the grief.