My closet demon is messiness, that tends to get worse over time.
I have to make a conscious effort to get rid of old, ill fitting, or worn clothing, and find time to try on everything in the closet that may not fit right, or look right.
Some favorite shoes in a pile, that are way past their usable life? – I had to learn to let go.
You also have to put everything away when it comes back from the wash or dry cleaners.
Too many hangers? gotta go, gotta go!
It may not happen in a day (without extreme measures), but it can be done.
If necessary, get a closet organizer (from the big box store, container store, etc.) and carefully look at everything before putting it away. Strong lighting helps identify stained, worn, aging or discolored goods. Be ruthless – you can always get more.
Good luck with taming your closet demons! Fight the good fight!