The best extension setup is usually the smallest one. Every extension adds startup time, memory usage, and a potential security surface. The question before installing any extension is not "is this useful?" but "is this useful enough to justify the cost?"

Here is how I think about which extensions are worth it.

The useful category: extensions that fill browser gaps

Firefox does not have dark mode on all websites, session saving with named contexts, or a built-in new tab with custom content. Extensions that fill these specific gaps are worth having because they solve a real problem the browser does not address.

Dark mode on all sites: either Dark Reader or NightOwl. If you want auto-scheduling, NightOwl. If you want fine-grained control, Dark Reader.

Session saving: Tab Manager and Session Saver. This is a gap Firefox has had for years.

Ad blocking: uBlock Origin. This is not mine, but it is essential.

The useful category: information on the new tab

The new tab is opened dozens of times per day. It is effectively free screen real estate. If you want ambient information there — weather, tasks, stocks, news — a new tab extension has unusually high value per unit of complexity.

The key constraint: you can only have one new tab replacement active at a time. Pick the information category you most want visible.

  • Weather every time you open a tab: Weather and Clock Dashboard
  • Tasks you need to do today: Daily Planner
  • Market performance at a glance: Stock Market Dashboard
  • News from sources you chose: News Widget

Extensions that do not make the cut

Extensions that replicate phone features you already have: voice recording apps, timer apps, note-taking apps. The friction of opening these in a browser extension is roughly the same as picking up your phone.

Voice Notes is the exception here because it removes the app-switching friction specifically for quick verbal notes mid-research. If your use case is not "quick note while browsing," skip it.

Extensions that solve one-off problems: if you found an extension for a problem you have rarely, consider whether a bookmark to the right website or a keyboard shortcut in the browser serves the same purpose.

My current active extensions

For reference, here is what I actually have installed and use daily:

  • uBlock Origin (not mine — essential)
  • NightOwl (mine — auto dark mode)
  • Tab Manager (mine — session management)
  • Stock Market Dashboard (mine — morning check)
  • Daily Planner (mine — today's tasks visible)

That is five extensions. Everything else I have installed I have built myself and test periodically, not because I need them all running at once.

I built 11 Firefox extensions — see the full series.