There's another element to quotes that we're ignoring: the fact that folks DO compare quotes. Let's look into that for a second.
Say a customer gets three quotes: low, medium, and high. How is one to choose?
If the quotes don't spell things out, the customer is not any closer to getting the job done. He has no way of telling what was left out or misunderstood by the contractors. It's a crapshoot.
The customer simply must be able to tell, from the quote, what the price represents. The 'right' quote is the one that best describes what the customer is asking for.
We've all been there ... we go into a car dealer looking for a 4-door sedan, and the clown shows us coupes and station wagons. You know you're off to a bad start, because -obviously- the salesman either didn't listen, or doesn't care.
Now ... for the next hurdle:
"I didn't think it would cost so much."
Where do we go from here?
Again, the quote points the customer in the right direction(s). Either find the money, or scale back your needs.
Using the example I created earlier, our customer can reduce his cost by, perhaps, doing his own patching. Maybe a cheaper disconnect. Maybe relocating the air conditioning compressor. The point is that the detail let's the customer continue to look for a way to deal with you, rather than simply discarding your quote as 'too high.'
Perhaps we overlook that the quote isn't just a figure on paper .... it CAN be a sales tool. By describing the job in detail, you're letting the customer know you were listening, and that you care.
BTW ... did anyone else notice what I left out in the detailed quote? I just did, right now. I didn't say a word about the required service receptacle. There's a problem waiting to bite you. One has to be thinking about the details to catch that .... and the guy who gave 'just the minimum' also gave no clue whetherhe overlooked that receptacle as well.
