Staying at Celina's place has its perks and drawbacks. As a perk, is the price (is one of the cheapest in the area.) but that is as much of it. First, the bathroom was advertised as a private bathroom, but once you establish contact and show your willingness to rent the place, Celina tells you that her brother is temporarily living in the house, and if you don't mind sharing the bathroom with him. You accept as you think it is a last-minute inconvenient. But as soon as you arrive to the place, you realize you will be sharing the bathroom with another guest. The house has 4 bedrooms. One for Celina's brother Jesus (who lives there always), and the other three for the guests. So you will only have a private bathroom if there are no other guests (2 people share bathroom. Per bathroom). Once you enter the bathroom, the first thing they tell you is that you cannot flush down the mix of feces and toilet paper at the same time. First feces and then toilet paper. I found this very uncomfortable (they have post it notes to remind you). Also, the mirror is broken in a corner and the shower curtain is dirty at the bottom.
If you are planning to rent this place in winter time (as it was my case), refrain from doing it, as there is no heating system inside your room. Also, the windows are low quality, so the cold enters without any challenge at 3 a.m (as well as the street noise). The heating system is only available in the morning and in late afternoon, but not during the night.
All the doors screech, including your bed. The bathroom light doesn't work properly and the last day the kitchens light burned out. The room is side by side with the kitchen, so everything that happens in there, you can perfectly hear it. Consider there are no common areas for the guests to hang out, so the kitchen is a place to hang out. An issue, especially if you have to work/study and need to go to sleep early.
The kitchen is not properly cleaned on a daily basis. Finding food waste at the bottom of the sink happens on a daily basis, as well as dirty pans, etc. Celina's brother is used to put the dirty dishes inside the old dishwasher still with big chunks of food, so they stick dry in the plate, they start smelling awful, and once the dishwasher has *cleaned* all the plates and glasses, they still have tiny bits of food stuck to them.
I stayed a month, and they only give you one towel and one set of bedsheets. So, during winter you are unable to wash them as there is no time for them to dry, or it is raining outside.
All things considered, and if I had this information beforehand, I wouldn't stay in this place again nor would I recommend, except if you are on a tight budget and want to stay in the center of Madrid.