No one can accuse Firefox of being light on resources - and limiting your history can help.
Everytime your browser displays a page or image the history is stored for 90 days - that's the default. That's a huge amount of data for most users.
You can tune this down by going to Tools/Options/Privacy in Firefox and setting the number of days Firefox remembers browsing history.
- Select Use custom settings for history from the drop-down list.

- Choose the number of days and click OK.

