Approximating costs is not the same thing as bidding on a job. Not even close.
How many times have you heard a realtor say, "it just needs a little paint and trim"? Are you aware that casing, base, crown and a fresh coat of paint for a 12×14 room is around $1000 in materials? How many first time buyers do you think are? I didn't pull that out of thin air, that's what I spent on my daughter's bedroom last summer.
I work for my client. If he needs a number he gets one, but I often find it more helpful to describe a scope of work. They have even less of an idea what goes into the remedy than they do of the costs, and the sharp ones will begin to tally their own expectations. And no, that is not "designing" a repair.