You can configure Firefox
to to display a small notification, with the option to save your tabs at the end of each session:
- Type "about:config" in the Address bar and press Enter.
- Locate this entry (use the Filter field)
- Double click on it to set its value to "True"
- Close the "about:config" window
- As from now each time you close Firefox, you'll be prompted to save your tabs.
This document, titled « Display the "Save and Quit" message when closing Firefox », is available under the Creative Commons
license. Any copy, reuse, or modification of the content should be sufficiently credited to CCM