The only thing I do with FF as often as open it is....close it. The "Save and Quit" option on closing Firefox is missing in version 63. Ouch. Sometimes you want it to save your previous session and sometimes you don't. Sometimes opening Firefox and seeing a bunch of tabs open lets the person that opens it after you know that you were in the middle of something and that they shouldn't close your tabs. An "always restore previous session" setting doesn't cut it. The option to restore your previous session only works if you're the only person using the computer and you remember to do it. The "Save and Quit" prompt in every previous version is the perfect solution. Sure, after a certain version, you had to turn it on once for each install in about:config, but lots of people did that. Why would they remove something that many people find crucial?