Since the advent of Firefox 4.0, history settings are based on your system specs. Firefox calculates how much history can be stored without affecting performance. You cannot change that unfortunately.

If you click the orange Firefox button and go to History, Clear Recent History, there are additional deletion methods in there, but they cannot be performed automatically I'm afraid.

See also History settings

Thanks Xircal, I appreciate your clarification. I am not a developer nor have the time to work my way through on creating an add-on soooo How does one go about suggesting that this become a feature of the next update? I also have a suggestion about THUNDERBIRD to make it more user friendly however I have been unable to find a place which will accept suggestions....I tried wishlist without success. Do you know if and how suggestions are possible. Cheers TG

Best place would be the dedicated Add-ons forum @ https://forums.mozilla.org/addons/

I appreciate you taking the time to let me know. All the best Xircal...TG

You're welcome.

Could you please click the "Solved It" button next to the post which solved the problem for you? This will help others searching for a solution to the same question.

Thanks.

I cant say that it was a problem. I can say it was a suggestion and as yet I can see no way that I can make a suggestion without going through and learning the Add=on process. Which as mentioned earlier I neither have the time nor the skills to do. I wanted to find a place where I can leave the suggestions that I have for someone who is capable of creating an add-on.

Try this one instead then: http://getsatisfaction.com/mozilla_messaging/

THANKS XIRCAL As well as giving praise and thanks to both the concept of MOZILLA and the online products that it generously offers freely on line I would also like to give thanks to the mentors that take time to help inform and educate us. Suggestions. Make the browser history in FIREFOX setable at a time frame ie CLEAR HISTORY EVERY 2 WEEKS OR EVERY MONTH rather than the all or nothing options we are currently offered. Also with THUNDERBIRD ( I have downloaded the latest edition Thanks) I would like to suggest coloured buttons for both the GET MAIL and SEND as they are most frequently used by ordinary garden variety end users like myself. I would also like to suggest that they get put on the end of the buttons more towards the middle of the page rather than the far left corner....when I finish typing an email I am usually in the middle or just to left of the middle of page and having the send button directly above rather than far left would be much more user friendly. ALSO as it would be more centered then it could be make bigger. THanks for reading and considering. I do not have the time nor the desire to learn how to do addons so I thought I would throw it out there to the creative community that is the driving force behind the upgrades and let you PLAY with it. THANKS

You can remove history for set periods of time manually by doing the following:

1. Click the orange Firefox button and go to History, then Clear Recent History.
   
   
2. In the menu at the top, choose a time range to clear, then click the arrow to get the items which can be cleared.
   
   
3. Uncheck those which you want to keep, then click the "Clear Now" button.
   

A quick keyboard shortcut to open the menu is CTRL+SHIFT+DEL

Another quick tip for you.

1. Click the orange Firefox button, go to Options | Options.
   
   
2. In every menu for which there is a button i.e. "General", "Tabs", "Content" etc., there's a button at the bottom on the right called "Help". Click that to access the same Help articles which are often posted in this forum.
   

Each of these articles contain links to others which are relevant to that particular subject.

Incidentally, Foxit Reader (which you appear to have installed) has just released a security update, link here in case you're not aware of it: Security update for Foxit Reader

That clears the recent history.

This is about the opposite: keep recent history, but remove older history and that is no longer possible.
In previous Firefox version you can set for how many days to remember the history, but now you can no longer specify for how long you want to keep history.
It is all or nothing and you can only specify how many pages to keep.

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