My sewing room is the living room so I try to keep it clean but lately it's become a bit of a mess. I haven't had the thread problem, but I'm also really paranoid about my nutty cat eating thread - I've caught him at it before and had to pull a big long strand out of his mouth/throat and that wasn't pleasant for anybody. So I make sure to throw away threads as I snip them and when I leave my sewing area I'm now in the habit of giving the floor a look-over and picking up any thread longer than an inch or so. (Although there usually aren't any...I don't seem to drop thread that much.)
My room is the worst for clutter, though. I have vintage sewing machines lined up under one table but ran out of room and now they're lining up on top of the table too and perched in other odd spots. (And I don't really have that many, just no room.) I pre-wash before I stash my fabric but I'm also really lazy about it, so that means there's probably 20+ yards worth of new fabric folded and piled up on the table, waiting to go through the wash....all the fabric I've bought since August or so and didn't need for an immediate project. (Lazy, lazy, lazy) My cutting table is only half-useable; the other half is piles of fabric I had pulled to audition and never put back, piles of paperwork (receipts, drawings, patterns, instructions...), and just random "stuff" I haven't found a home for. It's sort of neat (in neat piles anyway) but it's been nagging me so I need to get that cleaned up.
I don't eat in there or drink anything other than water; and the animals are mostly kept out of there, so it stays clean in that respect. And I'm constantly bustling around and fussing with things in there so nothing ever gets dusty...it's just way too cluttered. I really need to sort some stuff and move some of those older machines out of there...it's a sewing room, not a sewing machine repair room!