I've used a "lad" recently to
1) drill holes for pipe runs, fix pipe clips, cut pipes to length, do a few soldered joints out in the open
2) help running round a house on a powerflush (£5m house, central London)
3) help fix radiators
It doesn't take a lot to be useful for that sort of thing, but I did have a lad once who thought timber joists had to have wall plugs in them to take a screw for a pipe clip...
Number one requirement is honesty. As soon as I have any suspicion that it might NOT be ok to leave you with my stuff, or in a client's house, you're out. Not that I would leave you in a client's house for a good while...
I've often thought one could put a sheet of questions together, with questions like the following (off the top of my head)
Not knowing isn't too important, it just restricts scope of work.
What sizes does domestic pipe come in - copper, waste, overflow, the other waste..
How do you fix something like a heavy wall cabinet onto a plasterboard wall?
What's lath and plaster and how do you fix anything to it?
What's the thread on a 15mm compression fitting?
How does an AAV work?
WHat are the rules for notching joists?
What's the VAT on £80?
What's the slot for on a slotted basin waste?
Why do basin wastes usually leak?
How do you connect a tap flexy to a tap which has a solid copper tail?
Can you use compression fittings on gas?
What are the problems with pushfit, or endfeed connections?
WHat's a street elbow?
You're going to do some solder joints under a floor. WHat kit do you need?
WHat size SDS bit would you use for a red plug?
There's a window, there's its radiator. How do you hang the rad and how long will it take you?
Acceptable answers:
A right one - there's usually more than one
"I don't know. please help"
"I think xyz" is that OK?
"Just a mo I'll find out"
"I've used xyz before but would you agree?"
"I've done a lot of these so I'll just take care"
Unacceptable answers
"Xyz will do I'll have a go with that"
"Book says xyz but I have no clue - I'll have a go anyway"
"It doesn't matter"
"I've got xyz, it will have to do"
"Never done it but I don't see any problems so I'm starting"
If you're on my wavelength, and can do odd days, my email's in my profile. Most of the time I'm around Surbiton - Wimbledon - and west of central London