I wrote about four years ago that one of the main reasons I still use Firefox as my default browser is because of the fantastic NoSquint extension, which allowed me to persistently set a larger text size for readability.
It was with great sadness (and distress!) that I discovered today that NoSquint is no longer being maintained, and that it has stopped working as of Firefox v47.
Before I go on to alternatives, I have to publicly thank Jason Tackaberry for 10 years of fantastic support for this extension. That NoSquint has worked flawlessly over 10 years of browser development is no mean feat. Although it is a great disappointment that he feels he can no longer maintain NoSquint, I am nevertheless hugely appreciative of all the effort he has put in over the past 10 years that has made such a massive difference to my internet experience.
Now to alternatives. The two that other NoSquint refugees are gravitating toward seem to be ZoomPage (recommended by Jason) and NoSquint Plus. The latter seems to be an attempt at replicating NoSquint, but falls a fair way short at the moment. The deal breaker for me is not being able to see the current zoom level as a percentage.
For ZoomPage, it seems almost functionally complete, but the settings aren't very intuitive. It took me about half an hour to figure out how to control the zoom in configurable increments (hint: other than the increment setting on the Zoom Levels tab, you also have to check the box for 'Zoom In/Out - use zoom step' on the General tab).
ZoomPage seems to be almost there once you figure it out, but it lacks the ability to use both text zoom and page zoom simultaneously, which I have used occasionally. I think I'll be sticking with ZoomPage for the time being, but an ideal situation would be for someone skillful enough to fork the original NoSquint code and keep it maintained for current versions of Firefox.