Documentation is part of the deliverable
Certificates, test results and what was installed where. Reconstructing it later is painful and sometimes impossible.

Electrical
Electrical work is judged long after it is finished — at inspection, at sale, at the next fault. The record has to be as good as the workmanship.

What the work actually involves
Certificates, test results and what was installed where. Reconstructing it later is painful and sometimes impossible.
You quoted a socket and found the circuit. Every unpriced discovery is unpaid work unless it is captured.
The property history from four years ago is what makes the return visit efficient.
In ManePilot

Questions
Yes. Work history stays attached to the customer and site, so a return visit opens with what was done last time.
Additional services can be added and sent as an estimate for approval before the work proceeds.
Related
Set up your services once, and the schedule, booking page and invoices all work from them.