My bench is in the basement, and there was a large piece of brownish-tan area carpet on that side of the basement, when I moved in. Small parts disappeared into it.
Just before Christmas 2008, four days, in fact, my hot water heater finally rusted through and leaked all over the place. So, I had a reason to rip out that carpet. That left the cement slab floor, which was painted a medium gray. Parts still disappear, viewed from the eyeball's normal operating range of about 4 feet off the ground (no, I'm not a hobbit, that's roughly the elevation when I'm seated at the bench).
Whatever the floor surface, I use a small flashlight, laid on the floor, so that small objects on the floor will cast shadows and be easier to find.
I've seen jeweler's aprons, which attach to the bench to catch small bits that fall from your work. Putting a sheet down is roughly equivalent.
Probably no way to eliminate losing parts altogether, but maybe a workspace lined, floors and walls, with panels faced with opaque white plexiglass, with lights embedded, would give us more favorable odds.