As someone who is currently training an apprentice, I can assure you he doesn't justify the work for a full wage - this is not meant in a negative way, he simply doesn't have the experience for it - we've all got to learn somewhere. He's getting valuable experience from it, but in terms of the company getting "free work" or whatever you want to call it, it's quite the opposite, I'm having to do extra hours and take time off my actual work in order to plan things for him to do and train him. If we were paying him a full wage on top of this, we just wouldn't be doing it at all.