StoreTab Firefox add-on allows to save set of opened tabs with single click after that when you close browser and whenever you want those tabs back click restore button to let StoreTab restore those tabs in Firefox.
After installing this add-on StoreTab icon will not show in toolbar, you can click Toolbars>Customize and drag and drop StoreTab icon on the toolbar.
There is another built in feature available in Firefox to restore last closed tabs and windows session restore feature when user selects “show my windows and tabs from last time” in Options.
What StoreTab makes is you can able to load saved tabs on any active window any time user wants.