@Jules, yet another good suggestion!
I just did a survey, and about half of my Catalog designs inflict this suffering upon me:
Architect’s Adjustable Table Lamp
Augmented Robotic Manipulator
Desktop Sugar Monster Box
3-Pocket Executive Card Wallet
All of the above designs were ‘per print’ purchases. I’ve been following the guidelines for single-use files, which per @dan are OK to do a test-firing on cardboard for practice, fit testing, or in my case, fine tune the process of adding an engraved image to a Catalog design file before going live with the final source material: Catalog “per-print” ground rules?