A good estimate requires thorough knowledge of construction materials, methods, and building codes. It relies on a thorough inspection and the ability not only to see the faintest indications of damage, but also understand the implications of those signs. A spot on a ceiling or wall, a bent piece of metal at a roof junction, or cracked drywall next to a window, are good examples. Many insurance adjusters would just offer a little cover-up paint, a piece of new flashing, or a drywall repair minimum. And they would be almost certainly missing the real problem.