Depends on the materials the sub is made of. Foam surrounds are subject to decay, prolly not from cat hair though. I would imagine moisture (excessive humidity and such) would be the biggest threat to the surrounds (if foam) and the cone if its made out of a poorly treated paper.
Best thing to do would be too wrap the sub anyways. Its not gunna hurt. better safe than sorry anyways, right.
I stored a couple of Vifa soft dome tweeters in a hallway closet for a while (1-2 years). A lot of dust has colected on the diaphragm and perhaps in the voice coil as well. I have played them just recently, just to see if they still work. The answer is yes, but they werent as crisp as a new set.
You ar ewondering about subs, so this is a lil different. The subs may have a vented pole peice, or dust may get in through the spider, who knows.
If you boxed them and then wrapped plastic on them, it may improve clenliness and may preserve them. Always store the woofers with the cone firing sideways, that way the suspension doesnt get weaker.
