When a homeowner wants to list their home, they usually know what they want to list their home for. I recently went on a listing appointment, and he is down the street from my client. Because they did so much in their backyard, he automatically thought his home was worth much more.
So much goes into the value of a home.
On top of these points, it matters whether you are comparing to a similar style. Ranch homes are usually worth more, as more buyers would prefer a ranch, no matter what their ages. Do you back to open space? Do you have mountain views, or a smidge of a view? What is the lot size? Land matters!
Over my many years in the business, I have been to several classes with the instructor being an appraiser. They have given us a basis of what values are depending on each and every home.