Getting to a part you can hold
A model on screen hides problems. A part in your hand does not. Rapid prototyping exists to close that gap quickly and cheaply enough that you are willing to be wrong twice before you are right.
Send the model, get a quote inside a working day, have the part in 2 to 3 working days for most single items. Change it, send it again. We price each iteration on its own so you are never paying for revisions you did not need.
Design feedback comes with it
Slicing a model exposes things a CAD viewport does not. We see the wall that is 0.6 mm and will not survive handling, the overhang that will need support in a place you cannot reach to remove it, the 5 mm hole that will come out at 4.7 mm because of how plastic shrinks and sags.
That feedback arrives with your quote. It is not a separate consultancy line, because catching it before printing is simply the correct way to run the job.
Moving from prototype to production
Once a design settles, the same file moves to a batch run without starting over. The profile that produced your approved prototype is the profile used for production, so the parts you signed off are the parts you receive.