Well, someone has to create the models. If You're lucky and there's plenty of good modellers in Your use case / hobby, good for You. Have fun printing. What th

Well, someone has to create the models. If You're lucky and there's plenty of good modellers in Your use case / hobby, good for You. Have fun printing. What the OP however refers to is the "rapid prototyping" that 3D printers unlocked for masses. If You learn even some basic modelling (e.g. few primitives in OpenSCAD for programmers), it's trivial to do test fits and whatever gigs You need. I haven't realized it myself until some months ago I needed a small funnel for a bottle. After some thinking I realized it's much easier/faster to throw together a difference of two cones and two cylinders in OpenSCAD in about 10min and print it in maybe another 20 than spend the time looking around stores to find some close compromise.