My most commonly used fasteners for prints are m2 countersunk self tapping screws like these.
They’re small, but generally stronger than the prints they’re going into. If it’s something that may need to be disassembled and reassembled, I’ll use M3/4/5 socket-head cap screws and nuts or inserts.
I also keep a variety of magnets on hand to imbed in prints.
Then, of course, there’s bearings, threaded rod, aluminum extrusions, hinges, hookup wire, electronic parts, clear acrylic sheeting, etc.
My usual scheme for purchasing hardware goes something like this:
Create design and bill of materials > buy a bulk pack of hardware that includes the specific parts I need, plus extra if it’s cheap > store extras in 3d printed modular drawers, adding more drawers to the stack as needed.
I also travel for work and have been missing my mk3s back home. I’ve been eyeballing the Bambu Labs printer to bring on the road with me. My company will ship things around for me as I travel to different sites, so I don’t have to worry about fitting it in a suitcase. I just have to worry about it being packable and shippable, which my mk3s in it’s diy enclosure is absolutely not. The bambu is marketed more like an appliance than a project, in that it’s practically ready to go straight out of the box. Presumably, this means it should be able to go back in the box and ship off to the next site.