Firefox: Live Bookmarks Refresh Rate

Enter about:config in the location bar. Right-click anywhere within the list of preferences and select New -> Integer.

When you get asked to enter the preference name, enter: browser.bookmarks.livemark_refresh_seconds

You will then be asked to enter a value. Set the value to whatever refresh rate you’d like. The unit for the value is seconds, so if you wanted the refresh rate to be 5 minutes, the value would be 300 (as in 300 seconds).