Regarding Firefox.
- Export your bookmarks to external device
- Backup your /home folder, including hidden files; if you can't see them press Ctrl+ H. Then press Ctrl +A to select all of your /home contents, Ctrl +C to copy to Clipboard, then go to external drive, create a folder, "17.2 home", open it, then Ctrl +V to paste everything.
Remember, if you have an SSD you don't need a swap file.
You will need:
/boot/efi (make bootable, flag set to boot, esp)
/
/home
Before undertaking any major update make a full image to an external drive with rescuezilla.
Something I forgot I posted: