allow yourself a space when doing something important. This obviously relates to a home computer too. Long periods of sitting and breaks When working in front of the computer for long periods there comes a time when it is necessary to stretch or - even better - to have a break, do something else, go for a walk and so on. The 10-15 year old guidelines for people working with personal computers emphasised the requirement to take a break every hour for at least 10 minutes in order to rest a person's eyes and generally have a rest. That was because of the small monitors and displays emitting some portions of radiation at that time. Since then technology has moved forward, we have much bigger TFT displays and by work standards there's no theoretical necessity to walk away for the computer every hour but it is still advisable. The eyes will still get tired as well as arms and hands from typing and holding a mouse and as well as the whole body from the prolong sitting. The breaks are necessary to restore the blood circulation, to clear the person's mind and give it a rest, to do something apart from the computer business. After all, when playing "Second Life" (the popular online simulation game) you will not be able to eat or sleep there in virtual reality -- you would still need to come back to the real life and do all the things here simply to keep yourself