I was taught to paint by a professional and when estimating the amount of paint needed, I always allow for a second coat just to make sure of coverage. We interviewed a painter who tried to tell me I bought poor quality paint without knowing where I purchased it, and stated he would have to buy all new paint. He had not seen the cans and was just guessing so I asked him where I should buy paint from now on. It was the same place I had purchased my paint and he wanted to charge me an extra 20 a gallon more than what I paid for. Needless to say, I have interviewed numerous painters and they are not all honest.
Jim also provided a color consultant. This is something that we would never have thought of. We had Shannon from Shannon Campbell Designs out to our home, and we went with colors that again, we would have never thought of. Our home colors are beautiful, and we have NEVER seen out exact color combo! Trust me, we spent literally months looking at homes, websites, etc to choose our colors.
If a quote seems high, ask the contractor what is increasing the price point. Perhaps it's something that can be negotiated, or maybe this business is just overpricing their services. On the other hand, be skeptical of any price points that seem unfathomably low. There could be a reason their prices are below the industry norm - perhaps their quality standards are uncommonly low, too.