I ALWAYS do terms and conditions for jobs over £50
For jobs like rewires I do 33% up front at time of booking and the rest on completion of the electrical works.
Went to one on Monday this week, fold needed a cooker connected and there was a 2.5mm taken off a 6mm to a double socket, no RCD, old consumer unit with mix and match internals.
Told the guy that he needed a new consumer unit, cooker control unit and a cooker outlet.
He said just do it, I said I would email them a quote (including terms and conditions) , which I did and they accepted
After the job was done they tell me they have been to trading standards about the last guy (handyman who 'did' electrics) and are 'taking him all the way'
So glad I insisted on terms and conditions etc.