In case you're mad at yourself for closing your precious window with all the right tabs opened, note that Firefox allows to reopen recently closed windows
I generally have a "home" Firefox window with my most used tabs pinned. Sometimes I close it before another window, so I was frustrated to "lose" it and having to redo my pins. But recently I discovered this feature. Joy!
How would people function without knowing this?? Maybe I'm just young, but this has been a thing as far back as I can remember (maybe 2010 or so), on all browsers I've used (Safari, Chrome, Firefox).
Shift+ctrl+T is usually the keyboard shortcut to bring back closed tabs
Shift+ctrl+N is to bring back closed windows (doesn't work on private browsing windows)
I wish Firefox had a method to restore windows after a restart. Losing all my tabs across multiple windows due to work required updates is a huge pain.
It also persists through a reboot, so if you shutdown or reboot with tabs open, it will ask you to restore the previous session when you next start it after the boot.
If you didn't restore it, but didn't open any more tabs, you can close it again, reboot, etc, and this option will still work to get your tabs back when you're ready.
It works until Firefox applies updates and the next time you open it it automatically loads a "what's new in Firefox" tab erasing your previous session. Then you're SOL unless there's some way around that.
I know this, but I'm peeved that when I shut my computer off with Firefox open, I have a 50/50 chance of it automatically bringing all my tabs back on the next launch.
Uh, you can also use these things called bookmarks to save commonly accessed webpages… also this is a feature of literally every web browser since checks notes forever.
@OP When you have continue session on, closing Firefox using burger menu->Quit restores all windows. I assume this will also keep the pins even without continue session.