I’m glad to see you’re giving it some thought 👍
I don’t have any specific terms, I think its difficult to have set terms with so many variables.
However, here’s what I find works.
Communication – If your not sure, run it past the fitters, ask the fitters how they want the job supplying
Help them out – Try and make their life easier, put things in order to make their life easier
VISUAL – Give them a visual, number of times I’ve been handed a box of bits and told to fit it.
We tend to hand all of this to the fitters in a document, confirming everything that was discussed and agreed, contact details for site, ours of there’s a snag, Risk assessment of required.
The grey area I don’t like is if the fitter did the measurements and they happen to be wrong.
I like to think what subbies we do use, appreciate us making their life, and the job easier. If they still cock it up, they’re probably not very good.