Chair-Only reason is that you never know when you might need them. A few years ago there was a fire in the building and I had to scramble to put something on. Ever since on my chair which is right near my bed. Never stopped that and no fires!
I will sometimes put mine on the floor until the next morning. Then the next morning I put them in the laundry basket. Hanging clothes that aren't dirty go back on a hanger (I don't want them to get wrinkled!) and I'll hang them on the handles of the dresser. Then I'll put them back in the closet the next day.
Mostly on the floor. Anything that can be reworn (jeans or sweatshirts) usually go back away the next day unless I'm wearing them the next day, and anything that needs to get washed goes in the basket the next day.
I put pants, jackets, and sometimes shirts I've only worn for about an hour on a chair full of still wearable clothes and then socks and underwear and most shirts get thrown into a corner with a laundry basket.