By monitoring a particular technical field it is possible to keep an eye on general developments. It is in this way also possible to see the direction in which specific competitors are heading. An additional advantage is that it is possible to receive timely notice that an undesirable patent has been granted. Since the period for an opposition to a European patent lasts for nine months following grant of patent, it can be important to be aware of grants in good time. Another objective can be to identify when a particular technique is no longer protected and so becomes accessible.