Fix Price vs. Time and Material Contracts « Programmers Stack Exchange Blog als; you sold yourself as experts with statements like “We’ve done this kind of stuff a hundred times before!” If you cannot properly estimate a project, you have no right to call yourself experts on the subject matter. If you would never tell your prospective client the real reason you are proposing T&M, your reason for choosing T&M is simply not valid, and likely unethical. You did the Estimate, you are the expert, and it’s your job to know how long it will take and what problems may arise. (I’ll say it a second time: You are a professional; accept responsibility for your estimates) in Public bookmarkswith contracts