The number one recommendation that we have for homeowners that selecting a contractor to complete a remodeling project, install custom cabinets or other project is to make sure the contractor is familiar with the architectural style and is capable of executing that style above expectations.
Just like in any profession, there are some carpenters and cabinet makers that rely upon putty, caulk and other materials to cover up imperfections in their work. The photo below show one such questionable butt joint in the top of a twelve foot long Walnut bookcase. In my opinion this is unacceptable for such a visible piece of furniture. The second photo shows a poorly executed mitre joint that required a lot of colored putty.
As the homeowner in the greater Seattle and Bellevue area, be sure you ask your contractor some tough questions and let them know your expectations.