I have had 1 to 2 years of Firefox hangs, crashes and more. OK, maybe my PC is bloated or I got some bugs. SO I completely reinstalled Windows 10 from scratch. Guess what? Yep, still having a lot of hangs and crashes . So, it was NOT me!
I migrated to Chrome. Let me tell you though, as an addon developer and code contributer for Firefox, I know Firefox is much better in many ways! Bookmarks, better development tools, better integrations and little bells and whistles, more secure, etc. but it doesn't weigh up against hanging or crashing every hour or so.
After one year of reporting all my crashes, I am OUT A THERE!
Sorry, Mozilla, you are good, but you have a serious problem there.
Goodbye and thank you for all the good years!