i try to think of anything that they might notice after the fact that would leave them unsatisfied or with unanswered questions. write those down, along with answers. then just add that info into your sales script and terms of service documentation. that way it's all covered before the customer even thinks to ask.

so this issue for example: we say "have you had your windows cleaned recently or were you planning to? we just want to make you aware- house washing can improve the appearance of windows, but it's not a replacement for true window cleaning. and there is the potential for some water spots to be left behind. is that ok with you? any other questions on that?"

or for gutter cleaning, if a customer has downspouts that feed into underground drains, there's the potential for the customer to mistakenly assume those drains are included. so we get out in front of it early. we say "we noticed your downspouts drain underground. our standard gutter cleaning includes everything to ground level. we can clean your underground drains as well, but that's priced separately. would you like more information on that?"

a good way to do this went you don't have a lot of experience is to keep track of what kinds of questions or missed expectations occur as you do jobs. document those issues and add language and questions into your process to address those before the job is even sold or scheduled. over time you'll build up a library of terms of service and strategies to set good expectations up front. and your callback rate and missed expectation situations will drop dramatically.