I think there are two ways to approach business decisions involving provided services to customers:
1) How can I get my customers to pay extra for this service? 2) How can I find a way to give my customers this service without any extra charge?
Which path you take depends upon the goals for your business. A goal of delivering maximum short term profit will push you towards #1 and a goal of providing your customers with the best possible service (which I believe leads to delivering maximum long term profit) will push you towards #2.
I love delivering as much as I can to my customers. One of the ways we do that at Shepherd Dog is our pricing. The maximum we charge is the amount of our initial estimate, which is a typical way of doing fixed bid pricing. But we take that one step further and reduce the price our customers pay if we work fewer hours than we estimated.
I am always looking for ways to deliver more to customers. I believe it is key to long term success in a service industry.