I dissemble most things over a great big stainless steel bowl with one or two large speaker magnets in the bottom. Usually works pretty well. Got a lot of techniques for doing the floor search, up to and including throwing another one down in the same spot to try to track the motion... Most of the time its not worth looking for anything that does get dropped, unless I want to find something lost three projects earlier.

My father was working on his X-19 and a large spring on a compression tool popped loose and flew across the shop. Big red spring, we saw it flying off in a general direction, so knew what corner of the shop to look in. Not there, so started spreading out the search pattern. After over an hour, lots of cussing(even more than working on a fiat usually calls for)and still could not find it. Moved everything looking for it. Eventually found it where it had bounce up under a roll-away and hung up suspended just out of sight.