Okay, tell me if this is too gross. In one day, I only use one glass/mug. I just keep using the same one. If I'm drinking water or juice or (heaven forbid), soda, I just keep on going. If I have milk, I give it a small rinse. If at all possible, I re-use my other utensils. This is clearly not always possible or healthy, but is a plate you had a sandwich on really dirty? Oh noes, crumbs! I know some people who will have a glass of OJ at breakfast, soda at lunch, and milk at dinner and use THREE cups. Just seems weird to me.
...maybe I'M the weird one.