It depends on what work you have and how fast it needs to be done.
The problem with little exp people is they can take 2-3 times as long, need to be watched, the quality of work tends to be lower, and a better chance of dumb mistakes.
A $25 an hour guy may pipe somthing in 3 hrs. Cost=$75 (not even figuring taxes & etc.)
A $12 hour guy may pipe the same in 6 hrs. Cost=$72 Some bends may look bad, box hight off a bit, too many pipes in a box, 2x4's cracked from drilling, drill bit dead from nails, etc.
I can see how some Co. on a thin proffit margin can make it work. To me it seems like a bit more $$ payrole per job will give a higher quality.
Good things about an apprentice:
They can do manual labor just as fast or faster than a journeyman.
Apperntaces tend to be yonger and have more engery.
Some journeymen may hate a job with manual labor or unplesent working conditions (attics etc..).
They have more of a open mind on how things can or should be done.
The problem with some experianced guys are they can be set in their ways. Maybe they don't always follow code and just say it's allways been done like that. Or they may not want to go the extra steps to do a good job when the min. is their standared.
Didn't you say you don't network wires? Something like that could drive some JW crazy. They may disagree more a not be happy with the job over dumb things like that. An apprentace just tell em that's how your Co. does things and they are fine.
I would also guess taht apprentaces are a bigger risk of injury. But I think they would be less likely to milk an injury if it happened.