Oil spots, grease spots, glue spots, leaves that blow in when the door opens, spiders, beer bottle tops, cigarette ashes, cigar ashes, the occasional munchie crumbs, and various lawn care equipment is put wherever it will fit. It gets swept or blown out with the leaf blower whenever I get around to it, or if I know I'm going to be wallowing around on the floor underneath the bike changing fluids, etc.
1/4 of the basement does have a piece of carpet, which is underneath my 8 foot Brunswick Pool Table.
I have an aversion to painting perfectly good concrete floors, as you then just get into a cycle of having to do it over and over again. I guess the epoxy would work better, but I don't mind the look of concrete at all. When I worked in maintenance for UAB hospital, the Inganeers (who became administrative directors, managers, etc) in their infinite wisdom, used to make some of the helpers paint the machine rooms, which had floor drains, water dripping from this or that piece of equipment...all I ever saw was that the paint would bubble up and peel off regularly, so I always considered it a waste of time and money.
Not saying that a nice, clean, well orgainized garage or basement is not a good thing, but I'm just not quite that anal in my older years.