Reselling the work is a great way to make economies of scale so much so that many of my colleagues even specify it in the contract “the intellectual property of what I do is mine, you can use it as long as you pay me the fee and also I can resell it to one of your competitors.”
I use a perhaps less clever but more ethical strategy: I will never work for one of your direct competitors. This means that if you are a dentist in Monza I will probably only agree to work for a dentist across town or in a neighboring city.
That is why I always ask, before accepting a project, what you are involved in and what is your territory of action.
