Third, you should withhold a small amount -- say 10% -- until the project is "complete." Be considerate, however, about the definition of "complete." If the original estimate and project have been completed, the installer deserves payment in full for a job well done. That's because it is! AND, reality of your situation may be even more brutal than all that suggests. You may have the misfortune to be situated near to an extremely well-resourced department store's window display or a TV store w...