A relative reached out to see if I could replicate a part if she sent it to me. I said "yes" without being 100% sure that I could, or without really knowing what the thing was or what it was supposed to do, but I wanted to give it a shot. (Turns out it's a piece to hook a drink tray on to the corner of a card table.)
It took me a few weeks to get through all the steps, and printing the threaded bit was something new and slightly challenging, but I was able to work it out and I'm told it's performing just fine.
Printed part doing it's job:
Completed part, original object, and test prints:
When I first started designing and printing things from scratch, my process was:
Model and print a complete object
See what didn't work, re-model and re-print a complete object
Turns out this is expensive in terms of time, effort, and material.
What I've since learned (the hard way) is that it's often better to:
Model and print individual components, test their specific fit or usage
Re-model and re-print as needed
Assemble the proven parts into the final model and print
While the second method involves more steps, I believe it ends up being much faster, less wasteful, and makes each revision more productive.