Mozilla Firefox allows you to easily restore the last session of your Firefox web browser. For example, if you have opened four different webpages in four different tabs in Firefox and you close it down, your session is saved temporarily. Next time you launch the Firefox web browser, you can restore the previous session easily by choosing the option from the menubar. For this, all you have to do is press the Alt key once to display the menubar and then select History → Restore Previous Session. But if you have closed the Firefox web browser again or have restarted it, then your previously saved session is lost.
If you want to be able to restore the last session even after having restarted the Firefox web browser, you cannot depend on the in-built session restore feature of the Firefox web browser. For that you will have to use the SaveTabs extension for Firefox. Using this SaveTabs extension for Firefox browser you can save all the open tabs and open them any time later even after restarting the web browser a number of times.
After installing the SaveTabs extension in Firefox, you will be able to find an icon in the Firefox toolbar using which you can access all the options for saving and restoring your open tabs. You can save the current tab, save all the open tabs, you can restore the saved tabs, or delete the saved tabs at any time.
The SaveTabs extension is very easy to use and the save tabs last through the sessions as you open and close the Firefox web browser window. It is a great way to save some of your important finds on the internet so that you can access them later without worrying about losing them. But a more permanent solution would be of course bookmarking the webpages.
You can get the SaveTabs extension for Firefox from https://addons.mozilla.org/en-US/firefox/addon/savetabs/.