updates to kde and gnome

Hi all I have noticed that every so often packages on the kde and gnome sections of the SuSE downloads are updated. Is there any way of knowing whether I need to download the new packages. There doesn't seem to be any particualr explanation as to what might have been fixed/improved. As I use kde most of the time if I notice new versions of things like kdebase and qt I tend to download them anyway in case I'm missing something. But have I missed where I might find out if I really need to ? TIA Mike