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it would have been significantly more $$ to have them do anything other than a range of about 3 shades - white, builder's beige, and a cream color I think. We got to pick one trim color and one wall color. Anything beyond that cost more. So we did white so at least ceilings and closets were done.
The other big problem - we'd have also been on a tight deadline and had to have picked custom colors before drywall was even in - much less light fixtures, flooring, cabinets, furniture, etc. So picking a color that would have looked nice in a finished house based on studded walls? Bad, bad idea for us. We knew that until we lived in the house and saw what light was like in it and how paint samples looked that we'd never end up with something we liked and paying for a custom color would have been a waste of money. If either of us had had much experience with picking colors and painting, we would have liked to at least have paid to do the area we are now doing gray, but we didn't.
The frustration now is that you pick something you like and can't reliably get it replicated. We didn't have too much trouble with the green/blue for the bathroom so I'm hoping that after this yellow and gray, other colors will be easier. This gray color is also what we want for the entire living/dining/kitchen area, entryway, and hallways so I'd like to be absolutely sure we like it before it's in most of the house and we hate it! People keep telling me gray and yellow are hard. So blue will be easy, right?!