I think installing extensions in Firefox is a bit too safe. Luckily, you can get rid of a lot of the coddling.

If you try to install from some unknown domain, a yellow strip tells you that you were protected. You have to edit the options, add that site to allowed sites, and then click the extension link again. That's four clicks more than I want - opening the options, adding the site, closing that window, clicking the link again.

Not only that, but even when the domain is trusted, you are prompted for permission, with a countdown so that you don't accidentally permit it.

Personally, I think one prompt'd be enough. If that. Since you need to restart Firefox for the extension to actually be installed, even accidentally giving permission can be undone safely.

I don't mean to say that this is how it should be for everyone, but I don't like these storms of prompts, and I think many experienced Firefox users feel the same.

The solution

The whole allowing domains bit can actually be avoided by dragging the .xpi link to the address bar, instead of clicking it. I can't recall where I read this, but it does work.

The MR Tech's Local Install extension offers a setting to disable the XPI install time delay.

This makes installation a lot less annoying. If someone knows how to get rid of the installation prompt altogether, please let me know.