What is the best way to go about dealing with clients that want A1 work but questions you on every expense?

In talking with the customer it would be stated in the contract that we will visit and other expenses that might occur.
In doing so there may have been something hidden behind a wall damage not seen
These things may happen and pictures will be taken to talk about extra costs.
This is not a common but may happen.

My company has a policy in place that addresses this very issue. When you have a client that want the best sometimes it takes a visual aid such as the pricing comparables of some of your competitors on the very same task they would like completed to shed a little bit of light on the reality of why it may cost as much.

First thing you need to make sure you have explain the customer everything you will be done …

Second price every single item separate …

If you have explained well the customer , you should be ok with any project

We do a lump sum conctract. So what you sign for is what you pay for. No hidden fees. (Concrete; Staining; Overlay)

Typically you run into this situation when you have a "Time & Material contract."
I tend to stay away from this kind of contract but in some situations, where there is too many unknowns, it is the fairest way for both parties. You have to understand that most clients do not understand what work needs to be done in doing that job or what may be hidden in walls. The best way to help a client understand every expense is to give them a professional opinion of what they might encounter and a rough estimate of what the job would cost before you start. Be sure to keep a accurate track of the labor hours the task took, having all receipts well organized and taking pictures of all the work that was done behind the scene. All clients should receive A1 work along with A1 billing

The best way to deal with that type of client is being upfront. I always listen carefully to the client’s wants and needs. And I am always straight forward regarding pricing by offering multiple pricing options. Sometimes clients get excited about getting a project done that they think they can buy top of the line material at a law cost. By thinking that way, they lose the focus of what they called the contractor for in the first place. In fact, I personally go meet with the client so that I can lay out the best options. I itemize everything on the contract by offering multiple pricing options with multiple estimates. Finally, it is up to the client to decide which estimate to go with and sign the contract in order to proceed with the work.