It may require two or more tries to make good parts. Also, many factors must be considered such as shrinkage, cure depth, and draw speed. Understanding how the system reacts when changing these parameters requires lots of practice and experimentation with the system. Part accuracy depends largely on user experience. New users without a good grasp of shrinkage factors and the many operating parameters of an RP system typically do not make parts as accurate as experienced users.
Experienced users can better predict the outcome before the part is built.
RP is not best for all parts. RP permits you to produce incredibly complex parts and this is where the technology really shines. But it may not be practical to use the resources of an RP system to produce basic parts when conventional tools and machines are less costly to use, better understood, often more accurate, and offer a much wider selection of materials. Budget for the CAD installation. Allow for training and weeks of practice before expecting results.