In 3.6.16, the setting is located in Tools | Options | Privacy.

In 4.0, it seems to have been removed altogether and FF will save your history for 180 days by default.

I'm experimenting with the setting in about:config at the moment to try and set it to 10 days, but it doesn't appear to work as far as I can tell. The setting is called browser.history_expire_days which doesn't exist in FF4, so I added it.

It is no use to re-add those preferences to Firefox 4. Support for them have been removed. In Firefox 3 they still work, but no in Firefox 4 anymore.

• http://blog.bonardo.net/2010/01/20/places-got-async-expiration

@ co-rel, thanks for the tip.

@ dennisw, it seems Mozilla wants us all to have bloated history files by linking the number of pages which can be held without influencing performance detrimentally to the machine's hardware.

So to reduce it to what we as users prefer to have, you now have to create a different setting which is places.history.expiration.max_pages

To create it, copy/paste it into the filter at the top to get a blank page, then right click and choose New and then Integer. Paste the setting into the field and click OK. Then add the number of days you want Firefox to retain in the next field (I only want 10 days). I've attached a screenshot to clarify the procedure.

Thanks to all. Got both of mine set. My oldest is XP so I still have 3.6, an easy fix. dennisw

Oh, oh...I discovered a problem. places.history.expiration.max_pages refers to the number of seconds that Firefox retains history, not the number of days. I just lost all mine. :(

So if you've added it to about:config, right click it, choose Modify and then click Reset to disable it.

Quote:

for the sake of information we have two new hidden preferences:
places.history.expiration.interval_seconds is number of seconds between each expiration step, while places.history.expiration.max_pages is maximum number of pages that we will retain before expiring.