Half the surprises on site aren't really surprises. They're questions that should've been asked before anyone turned up.
A lot of on-site surprises have a familiar shape: access is blocked by something nobody mentioned, the property has a quirk that changes the job, or the customer wanted something subtly different from what got quoted. Almost none of it was hidden deliberately. It just never got asked.
Why the same gaps keep happening
Without a structured way to gather information up front, what gets asked depends entirely on who happens to be booking the job that day, and how thorough they're feeling. Some slip through every time, however experienced the team is.
Standardising the questions that matter
A reusable form - sent before a quote or job, covering exactly what your trade actually needs to know: access, parking, property age, photos of the area in question - turns "hopefully someone remembers to ask" into a consistent, repeatable step. Questionnaires exist to make sure that consistency doesn't depend on memory.
The verdict
The job that goes wrong on site rarely does so because of bad luck. It's usually a question nobody thought to ask until it was too late to.