Almost every difficult client conversation I have had traces back to something that was assumed rather than agreed on in writing: how many final images, how long editing takes, what happens if weather cancels an outdoor shoot. None of that is complicated to fix, but it has to happen before the booking, not after.
A short written agreement – even a simple email confirming date, deliverables, timeline and payment – removes almost all of the friction later. I send a one-page shoot plan a few days before every session covering location, timing and a rough shot list, so there are no surprises on either side.
Clients rarely ask for less than they were promised; they ask for more when the promise itself was vague. Being specific up front, even when the answer is a boring one, is worth more than being flexible after the fact.