Then you should first change your browsing habbits, and probably several other ways in which you organize things in general. And ask yourself if you really understand modern technology.

Second, you could save all the open tabs as bookmarks, with the Bookmarks -> Bookmark all Tabs command. It will save all open tabs in a new bookmarks folder.

Lastly, when you reopen the browser after the update, you can click File -> Reopen closed tabs, which will reopen all of those, even if you haven't bookmarked them.