When I have tabs open watching items on E-bay, I have to manually clear the cache (I leave history, cookies, and logons unchecked) in order for the pages to reload. If I don't, the page reloads with the same time remaining in the auction when I hit the reload button - even if it's 45 minutes later. If I reload after clearing the cache and there's less than 30 (or so ?) minutes left, the page counts down, and updates the page when the auction is over - so that part is working ok.
Firefox 3.6.8; Windows XP SP2 (PIII laptop won't do SP3)