I've recently done a little experiment and took a look at the first few websites which I have ever visited with my current Firefox profile and wrote them down. I was also a little bit confused, because I don't think that the things I apparently first ever visited in the Firefox history viewer were actually what I first ever visited.
A month or so later, I took another look at the first few websites I visited in the Firefox history viewer, but they were something completely different this time.
I'm very confused as to why this happens. Does Firefox automatically delete history entries which have a certain age?
For clarification:
Yes, I did click "Older than 6 months", and yes, I am also aware that history entries, which I visit again in the future automatically get moved to the top of the history list. I have also entered the URLs that I wrote down in the search box, but no results. So I assume Firefox deletes history?
EDIT: And if the answer is yes, is there a way to make it so that Firefox never deletes history entries? (I know it affects performance, but I'd rather keep all of my history entries permanently)
Best Answer
AFAIK there is only one setting in about:config that seems to control this:
places.history.expiration.transient_current_max_pages. On my machine it's set to 104858 (it says 'user set', but i have never and seem to be unable to change it's value). Interestingly in practice, that amounts to less than 6 months!!! according to this blog entry it's supposedly all my machine can handle (sure skylake, 32gb ram & 1tb ssd can't handle more ;-))...Assuming each history entry takes about 100 bytes (average page title + url + visited timestamp + visit counter (in my case)) that caps history at about 10MB, but i'd rather it taking 10GB and retaining more than 5 years...
real shame as this essentially makes firefox much worse than i ever thought it was...