I recently found a very nice plugin for Firefox called Save Session. This plugin allows you to save your current Firefox session.
The Save Session extension adds a new button to your File menu called “Save Session & Exit”:
When you click on this button it will close all Firefox windows and tabs. The next time you open Firefox the plugin will reopen all Firefox windows and tabs so you can start where you left
There are also other ways to save a session in Firefox but they aren’t as elegant as this plugin:
1) When Firefox crashes it automatically saves the current session. You can simulate such a crash by pressing CTRL + ALT + DELETE and terminating the Firefox process in the Task Manager. The next time you start Firefox it will ask you if you want to restore the previous Firefox session.
2) Firefox features a built-in feature to automatically reopen your previous Firefox session. Go to the Options menu to activate it, in the Main menu you’ll find a combobox where you can select the reopen all windows and tabs from the previous Firefox session. The only problem is that this will always reopen your previous session and that can be quite annoying.