If you are selling, I would recommend spending the money on the doors. I have sellers who have curtains and I always ask them if they could reinstall the doors. As a seller in today's market, you need to take away as many objections as possible before the first potential buyer walks through the door. Having an experienced realtor on your side during the process of getting it ready to list is invaluable, and can help you figure out which items you should spend money on and which items won't be as important. Good luck!
The answer to your question is no. All you need is a designated space for clothes. Depending on the price of the property you may wish to install doors before selling. Ask your agent if it will bring you in more money or a quicker sale.
Closet doors are not necessary to be considered a closet. Curtains or drapes are likely to be a turn off. If you are selling doors are the norm expected by todays buyers. If there is a small room with no closet it is not generally thought of as a bedroom....Doors generally hide the fact that many closets are too small for todays standards, so organizing and putting on doors may show better for any sale....Best to you..enjoy this great weather
What will happen if you use the curtains is that whoever is looking at the house will automatically say "we have to put a door on this closet", so they will add it to the list of negatives about your house or condo. When it comes to appraised value, they don't give value to whether you have closets or not, it is only the square footage that counts. What your house is worth to someone is a different story.