This is why I had all of my sweaters and long-sleeved knit shirts folded and taking up valuable drawer space. Until I discovered the proper way to hang sweaters:
Fold the sweater in half, lengthwise. The sleeves should be laying on top of each other.
Place a hanger so that the hook is in the armpit of the sweater, and the long side is next to the neck of the sweater.
Fold the sleeves up along the line of the hanger...
...then do the same with the torso of the sweater.
Now the hanger is wearing the sweater like a scarf :)
This way of hanging the sweater distributes the weight of a heavier knit, and keeps the hanger away from the INSIDE of the shoulders of the sweater, and hence, helps you avoid the dreaded shoulder nipples.