a. Is this a prob that afflicts mainly Plugins? It seems so, but then I have few to no Addons in other categories.  YES/NO
         b. Do Firefox's Auto-update & Chk for Updates features -Work for all add-ons tout court?       YES/NO

             continually babysit each 1, checking frequently w/each for updates ? 

        e.  Finally, there's no answer anywhere in general to the  Q: If I find an update to a long-outdated addon, am I supposed to
                 i. just go ahead and download it for a manual update?

I'm very confused re Addon updates, esp. PLUGINS. I've set them to auto-update, but not all seem to do so. AND even when I "check fr updates" I find none- but it seems there ought to be. E.g. plugins Itunes Application Detector 1.1.1, last updated Dec. 18, 2015; Media Go Detector 1.0.0.0, updated August 27, 2013; Nitro PDF Plugin for Firefox & Chrome 3.5.2, updated March 26, 2013. Since you allowed it, I did at vArious times disable or put some of these on "Ask to activate" or "Never activate" when I experienced security probs. I would have liked to REMOVE them from the Browser, but finding NO WAY TO DO THIS (my Q 2) the next best1 option was DISABLE or.... So Q1: a. Is this a prob that afflicts mainly Plugins? It seems so, but then I have few to no Addons in other categories. YES/NO b. Do Firefox's Auto-update & Chk for Updates features -Work for all add-ons tout court? YES/NO OR c. Do they only work under certain conditions? E.g. Plugin must be i. Enabled? YES/NO ii. Activated? YES/NO OR d. Must I ascertain case-by-case whether a developer has thought to enable this functionality on an add-on, & if not, continually babysit each 1, checking frequently w/each for updates ? This indeed seems to be the case w/e.g. "The Addon Bar (Restored) 3.2.9-compat-fixed-4," latest update May 4, 2016. I've never used it, cos I've never seen it; & in reading user reviews I see that though it's popular, it has a habit of just disapperaring in recent Ffox v.s. The developer responds to at least t2 recent user reviews by going to work on a fix & swears it's ok- indeed, the name suggests, at least 1, & possibly a 2nd fix- but for the life of me I can't figure out whether he's done another recent update or not, anywhere on the sites; if so, I can't find one. (I willsend him an email & wait for an answer: but is this going to be necessary in every case? e. Finally, there's no answer anywhere in general to the Q: If I find an update to a long-outdated addon, am I supposed to i. just go ahead and download it for a manual update? OR ii. uninstall the old v. 1st? I know I've bundled a bunch of Qs together, but they are all related, so I hope you can oblige. I've tried to simplify by numbering them etc.: if you can, just put the numbers/sub-numbering with Yes/No/ i./ii. as appropriate.