When I used to work for a council we used to book work in as minutes. We were given 6minutes for a socket, 3 for each gang of a switch and 21 minutes for a FCU (don't ask why).
When I priced work privately I just be realistic and understand that there are too many variables and so estimate time according to the room when it comes to second fixing, not each point.
When I priced work privately I just be realistic and understand that there are too many variables and so estimate time according to the room when it comes to second fixing, not each point.