Do your window screens have a few little tears or holes in them? Don't think it's no big deal, and too minor of a thing to bother contacting your R.A. or dorm maintenance crew. Leaving just one small hole in your screen is like flinging your door open to the entire insect world, as they can easily crawl inside. Still not concerned by the thought of some spiders, ladybugs or flies sharing your space? That's not your only potential problem. Did you realize mice can squeeze through a hole as small as a dime, while heftier rats only need a space as wide as a quarter [source: PR Newswire]? Now the idea of contacting your R.A. might not seem so silly.