I appreciate your taking the time to respond to my concerns, but honesty compels of me the admission that I'd appreciate it more if you could offer something more substantive than the browser equivalent of "Have you tried turning it off and on again?" Of course I have, and if it'd solved my problems, I wouldn't still be complaining about them on Hacker News, where the response is certain to include an overwhelming preponderance of "works just fine for me!"
On the other hand, per a decision made a couple of years ago, I also stick with the ESR release track rather than keeping up with the mainstream releases, because I got tired of having to restart for updates even more frequently than for performance reasons, and also of having the user-interface tablecloth yanked out from under me every time the major version changed -- on that latter point, incidentally, if I want Google Chrome's UI, I know where to find it.
It's possible that running Firefox 24 ESR means I've missed out on some recent stability and performance updates, although I had the impression that both sorts of fixes were generally backported to the ESR branch; given my prior experience, I'd be astonished (and delighted) to see those missed updates make a major difference, but who knows? Perhaps in June, when Firefox 31 ESR drops, I'll find myself astonished and delighted.