The main crime prevention purpose of marking your property is to make it less attractive to thieves.
Thieves know that if they are caught in possession of a marked item the Police can quickly establish it as stolen property, they are 'Bang to Rights' and in trouble!
In addition, the traceable property may be more difficult for them to "cash in" with another criminal or to a willing purchaser of the item. Of course it also greatly enhances the chances of you being re-united with the item.
Even if you think your property isnt valuable enough to mark, you should mark it so that if it is stolen, it makes it more difficult for the criminal to dispose of and far more likely that they will be convicted if caught in possession.
Total Security Products offer a range of Ultra Violet (UV) marking kits to invisibly mark your precious items, and a UV lamp to check that your property is properly marked.