It's not the best of habits yet I currently have 3109, recently migrated to Sidebery from Panorama View [0]. I'll likely go pruning soon, yet having time context of what I was looking at (by neighboring tabs and indent levels) is so useful for sparking my memory and associating ideas. I've tried using bookmarks and tagging yet the tooling around that is annoying enough I keep coming back to having an obscene amount of tabs open.

Ideally, I'd like a bookmarking system which allows for referencing tab history, past visits and other tabs viewed in each visit's timeframe, manual tagging, external references, and more, yet that doesn't exist yet. I've looked into developing such an extension, yet tab history APIs are clunky enough I haven't bothered going further. If anyone knows of other extensions that fill this niche, I'd love to hear of them.

[0]: https://addons.mozilla.org/en-US/firefox/addon/panorama-view... This used to be a built-in feature of Firefox, which I used until I was forced to switch to the addon.