Apart from basic turtlenecks, I hang up my knitwear (sweaters and cardigans) because I prefer to see most of tops hanging in one place. This simplifies my dressing process. I have the luxury of plenty of hanging closet space and take full advantage of it.
Although my knitwear is fine gauge and not overly heavy, I do occasionally get those unsightly “hanger bumps” on the shoulders of my sweaters. I loathe ironing and there is no way I’m going to pull out the steamer to straighten out the bumps. So I had to come up with another trick: I pull on the sweater, run the tap, wet my fingers and rub them quite vigorously onto the knitwear bump for 5 seconds. The damp rubbing flattens out the bump. Afterwards, I flatten out the wet bump even further with my fingertips. Bye bye bump and wait for the patch to dry, which takes about 10 minutes. Remember that the sweater has to be ON your body when you rub the bump with wet fingers.
You can also use “bumps be gone” bendable foam hangers. Several of my clients say it works like a charm. I don’t use special knitwear hangers because I don’t like the way they look in my closet. I know this sounds ridiculous, but we all have our quirks. Besides, my wet finger rubbing trick works too.