I create computer vision solutions. I wrote a camera abstraction class which I use for multiple clients which I open sourced [using "WTFPL" (1)]. I don't charg

I create computer vision solutions. I wrote a camera abstraction class which I use for multiple clients which I open sourced [using "WTFPL" (1)]. I don't charge my clients for the time spent on open source code that I write for their projects but realistically, I'm giving them free labor. It just seemed like more of a hassle to license it to them at the time. For my current client, I wrote a library that I license to them for a fee. When you license a library it is a lot easier to charge by actual value delivered than by charging by the hour. We agree on an acceptance criteria, they test it to show it passes, the pay me and then they get the source. The code I write for a client becomes the property of the client upon payment. This is an important thing to have in your contract. I had a local lawyer draw up my contracts. I spent some time on the researching internets making a rough draft of what I wanted as this gives the lawyer a list of things that I wanted to capture in the agreement. As an aside, I insist on a "10 day net". After 10 days out, the rate is increased by $50hr i.e. if I billed at $N per hour and they take more than 10 business days to pay, they pay me at $(N+50)/hr. (1) http://en.wikipedia.org/wiki/WTFPL http://en.wikipedia.org/wiki/WTFPL