Some clients are absolute pains with flat costs. They argue over scope, then argue over the definition of done, then they argue over features that were not in s

Some clients are absolute pains with flat costs. They argue over scope, then argue over the definition of done, then they argue over features that were not in scope and refuse to pay you until you do them (for free.) For these "special" clients, I found the best model to be a pre-paid declining balance retainer. Nothing gives more focus to clients than a slowly ticking meter. Further, i'd set the rate to be something that is worth even bothering with such clients.