Alternatively, you can use Ctrl-W keyboard shortcut.
(Sorry!)
I have five windows open with about 1000 tabs in each, no performance problems at all. It's great!
Yeah, because he'll be back to up hundreds of tabs again.
I find it useful to periodically prune, though. Save to Pocket or other "to read" list for things I intend to eventually read. Bookmark things I may want sometime, but don't need open. Potentially use Tab Stash to save groups of references for particular research tasks. Toss things that realistically I'm just not going to get to ever.
I've been doing this for years and have never, not once, looked at the bookmarks. But it gives me the peace of mind I need to close all tabs and start over.
And there are users of Firefox out there with >15000 tabs.
Two reasons for tab hoarding: 1) spatial -- related tabs are close together (frequently open a bunch of related search results; if I come back to them to continue later, they're all together). 2) history -- unlike bookmarks or history entries, tabs retain the forward and back history, so when you return to them you can know how you go there (go back to the search for example).
I do periodically clear out tabs, especially duplicates. The Tab Stats extension by glandium is very handy for tab hoarders
- I'm likely to return back to some of them. I might not know which ones. Typing in the address bar brings them back fast and the page does not need to be loaded again. Having the tab already open is also a strong signal that this is what I'm looking up.
- no noticeable slowdown anyway, Firefox is actually quite efficient.
- I don't care for taking the time of closing them progressively. It happens that I will close them all at the same time at some point when I feel like I need some clean up. Usually when I'm done with something.
- I think I learned to mostly ignore this part of the screen. Everything happens in the address bar.
In short, it's a combination of intentionally leaving tabs open so I can go back to them later without reloading the page, and not wanting to spend the time to manage them.
I usually have under 100 tabs open though, often even fewer.
With a good UI the unused ones just don't bother you anymore anyway until you scroll or filter them. They show me my train of thoughts without having to consciously organize anything. Unused tabs get unloaded from RAM anyway, so the cost of keeping them open is minimal.
A few years ago there was a version of Firefox that didn't slow down and opened quickly even at tens of thousands of tabs, but unfortunately it quickly regressed, so throwing everything out periodically is still inevitable:)