With a nod to BenMiller (above) - For the guys that do this stuff more than once, and can sit/stand at a table or bench:
When you disassemble/assemble the tiny springs into stuff like R/C cars and AR15s, try to do that part inside of a big/clear plastic bag.
It really cuts down on the trajectory when they launch.
When you disassemble/assemble stuff with lil-tiny setscrews and nuts and pins and stuff - remember that there exists a method that jewelers and watchmakers used to employ.
It's an upper body apron that fastens behind your neck like a bib, and extends to a tablecloth over your work surface. Anything that falls will fall onto/into the tablecloth or the part of the cloth that covers your lap, where it comes to rest within reach instead of somewhere 'down there on the floor/rug' area where you either have to stop and fetch it or you lose sight of it completely and usually forever.
And don't forget the magnetic bowl where you can drop the stuff you're disassembling, so it's all in one place, and not rolling around.