"Maker is just starting out, new kid on the block(doesn't have to be a new guy though) and takes an order for a knife, a knife which is part of his standard lineup. Things start to explode for the maker in terms of orders, demand, shows, etc.etc. Maker also goes through a huge spike in skills, abilities, equipment allowing more complex techniques to be used. A year or so goes by before that order comes up on the work bench. Maker considers it a model below his current skills and abilities. Customer still wants that exact knife. Maker considers it going backwards, and not indicative of what he can do currently. Also, in an honest self critique, original knife is not of the best construction, some elements are poorly carried out, and maker would be embarrassed to have another knife like it floating around in todays market......however,it was the best he could do at that time. Maker wants to cancel that order, make something more commiserate with his current abilities, style, and construction. Customer refuses and wants the original model. What does maker do?"
Tanya...make the knife. Period. If you want to do it with your improved skills and technique, and equipment...go ahead. If you want to make a better knife, but along same lines...go ahead. But, you should charge what you agreed to in the first place. I can't see how a knife buyer can complain about that.
Knifemaking on a scale where you are taking orders is a business...under promise and over deliver and you won't have a problem.
I have a friend who traded a few folders for a gun a few years ago. He is now making the knives...his folders are now a lot worth more than they were at the time of the trade. He says "tough tittie", a deal's a deal and he is making them at a lost opportunity cost. That's straight up business and upholding your word.
As has been said here, but not quite so succinctly...Sometimes you just have to suck it up and take care of business.