I don't put mine away either. But then, I don't really wear too many sweaters that aren't of the cardigan variety and most cardigans work throughout the summer in colder offices or work environments anyway. Besides, my closet (which is actually a spare bedroom) is big enough to handle all of my clothes.
Nope. So used to keeping everything out when I lived in Chicago and it could be 40 degrees in June or 80 that I don't bother putting anything away. I don't have that many clothes anyway though so I need to use what I got! :)
I do just because I don't have the space. Some stuff I'll keep out year round though because it stays pretty warm here so I can still wear short sleeves now but if its too summery I won't wear it.
