Rapid prototyping often means "trials and errors" because you usually don't end up with the exact part you need right at the first time.
It might depend on the design itself that isn't perfect and needs adjustments, or on some failures that might happen during the printing process (printer failures or material dependent failures) such as :

  • warping
  • delaminating
  • burns
  • filament sleepering or breaking
  • power cut
  • etc.

If like me you feel concerned about our planet and its pollution (and you should), you're probably keeping all your print failures somewhere, waiting for the emergence of a reliable recycling machine that could make new filament rolls out of your waste.

Or you could just use your imagination and artistic skills to produce unique 3D printing art...

CMYK 19X27