[BeetleB]

Here's a more intermediate approach:

https://addons.mozilla.org/en-US/firefox/addon/tabwrangler/

The basic idea: It closes any tab that has not been visited in the last N hours.

You can lock tabs to prevent them from closing (you can match on domain names, etc).

You can also see the last so many tabs it closed (1000? I forgot if this is configurable).

It's been fantastic. I don't need to manually manage tabs any more. I happily keep opening new tabs, knowing full well it will clean up after me.

[random3]

This sort of denies there was any purpose to keep the tab open to begin with.