We always need hangups, that is, somewhere to hang stuff, don’t we? When you have limited space for hanging things, use your doors where it is possible.
I have a very small entrance hallway. Except for the entrance door it has one door to my storage room. On that door I use an over-the-door hang up thing for jackets and bags and such that I use frequently. Also my guests hang their coats and such on this hanger as there is no space for anything else for this. This particular one I bought at Lagerhaus long ago. I like its colorful heads. No longer sold, but there are similar ones around.
On that very same door I use both sides for hanging things. On its inside I have two small over-the-door hangers.
Both hangers are used for bags for recycling purposes. They hang on the inside of the door to my storage room so you don’t see them unless you open the door. The one to the left is used for bulbs and batteries, the one to the right for plastic bottles to be returned to the store after use. A plastic bag with various paint brushes alos hangs there at the moment. It is always hard to find space for all that recycling one does nowadays. Hang them on hooks over the door works when content isn’t heavy.
I also use the door to the bathroom for over-the-door hangers. Here I only use the inside of the door, in the bathroom. There isn’t really anywhere in the bathroom to hang things, except for one single hook on the wall and smallish hooks for towels and then the towel-dryer. I need somewhere to hang my bathrobes and some other clothes. One of Ikeas over-the-door hangers solved that. When I bought it they only sold them in grayish metal. Nowadays you can also get them in white.
Except for the entrance door, I only have three doors inside the flat (not counting the sliding doors to the bedroom or the door to the patio). I only use two of them for over-the-door hangups, the one to the bathroom and both sides of the door to the storage room. I could use the inside of the door to the walk-in-closet, but presently have no need for it. Nowadays you can even find mirrors done for hanging over the door.
So, when there is no other solution for hanging things, use your doors.