Usually, they're after the first case when they come to me, and someone else "productizes" the "thing." Sometimes I have to do it.
Once when I quoted estimated time and hourly charge, a client (referred to me by a satisfied customer) left "in horror" saying "I can get someone else for 1/3 that!". That "someone" of course was a "programmer" with no '51 experience.
I repled, when you come back the charge will be higher.
He came back, and I charged him the higher rate and told him "next time, regular charge".
You do things like that when you have enough to do, had I been less busy, I would probably have replied, "I'll wait for you to come back" and left it at that.

Erik