What I usually do is say: Projects similar to what you are asking for, have taken me about xxx hours of work.. but our mileage may vary. If you don't like my pr

What I usually do is say: Projects similar to what you are asking for, have taken me about xxx hours of work.. but our mileage may vary. If you don't like my progress the first week, you can always fire me. Or.. for xx hours I can go as far as I can, then you can judge if it is worth it. My rate is high, but I usually over deliver per hour worked, so it is a good deal for someone who has already wasted money with "cheap" developers. The key is trust and communication, I do spend a lot of time talking with customers to make sure that we understand each other (I charge for talk time, texts are mostly free)