The Customer Bill of Rights.
You have the right to an overall plan, to know what can be accomplished, when, and at what cost.
You have the right to get the most possible value out of every programming week.
You have the right to see progress in a running system, proven to work by passing repeatable tests that you specify.
You have the right to change your mind, to substitute functionality, and to change priorities without paying exorbitant costs.
You have the right to be informed of schedule changes, in time to choose how to reduce scope to restore the original date. You can cancel at any time and be left with a useful working system reflecting investment to date.