Where I work (large university) the instructors and professors teaching engineering labs build pretty much all the setups for the experiments using 3D printers and off the shelf components. It allows them to iterate very fast on designs and can also change the experiments year after years, since they are not stuck with some expensive machine or piece of equipment. It really is an amazing technology.

I used one for a personal project I'm working on. I'm building a robot and had trouble finding wheels for it that fit my design, so I just made my own!! Got some silicon rubber strips from McMaster-Carr and now I have very fancy and functional wheels! Of course I am very fortunate to have access to a very good 3D printer, which is a few years out for most people.