Interruption software to remind you to take a break from typing
xwrits typetime=55 breaktime=5 &
xwrits will flash a window up on the screen when it's time to have a break. Click on the window when you start your break. When it's time to finish, it will change colour. You can also make it lock your keyboard to enforce the breaks, or cause annoyance to encourage you not to ignore it.
It is useful to make xwrits start every time you log in. In GNOME you go to Control Centre (usually under the menus somewhere) and look for Sessions, then the Startup Programs tab.
Manpage
SuSE also has its own break software. Look in the GNOME Control Panel under Keyboard.