Alot of my clients asked me why I dont take upfront payment curiously , everytime I have same answer: Because I know what I am doing and I know that I am going to finish it perfectly, well the question rises if someone dont pay , then honestly its not my loss because the system is transferred when they see the results , they said ok and send the payment , so if you ever feel stuck why someone is not trusting you ,remove the risk , show them the result , then take the fees. One more thing , be so damn good in your work , once they see the results , they have to pay the high fees too