The first step in any job is an on-site visit to see what the customer wants. At that point, I can explore their situation and ask questions about what they wish. Afterward, I will try to offer some opinions based on my 25 years of experience.
However, this is only the start of an initial consultation. An equally important part is the actual writing of the quote. Some remodeling contractors just give the customer a lump sum price. This can be very misleading. I make a strong effort to provide my customers with an itemized list.
I stand by my quotes, and there are only two reasons for me to change that value. The first would be an unforeseen situation. For instance, I may discover that a supporting structure was inadequate. The second reason would be if the customer changed their mind.