One party tells the other that, for planning purposes, “just give me a rough idea of what this will cost.” They emphasize that the estimate need not be exact. “don’t worry, we won’t hold you to it but we must have some idea of what we are getting into.” Trying to be helpful, you fall into the trap. Instead of being careful in your calculations, you make a quick estimate, generally on the low side because that is what they think they want to hear. Then, later when a formal quote is requested, you suddenly realize that the “planning purpose” number has become an anchor point in the negotiation. Recognize that a “planning purpose estimate” is likely to be more binding than it looks.