So my sister and I have a small age gap and are really close, she's the most important person in my life. However, since growing up age she never cleanes up after herself or cleans anything in the house. We do have a schedule for dishes and laundry but if I ask her to not just throw her clothes on the chair forever and let it build up she gets irritated like I'm this nagging old person. We both work full time and I'm a student too so I can't concentrate when the house is a mess but whenever I have a day off I have to clean the house or it'll look like a dumpster. I talked to her numerous of times and told her that I was tired to clean everything by myself like I was her maid and she said she would get to it but the right time never comes. I ask her nicely to do something, says shell get to it but a month passes and she still hasn't done the task. Is it too complicated to want to live in a clean environment? If I get angry then I care too much and there was times when I purposely left everything untouched to see if she would clean literally anything but no, she just really doesn't care. If you guys have been in a similar situation what can I do to somehow teach her that living in a dumpster isn't normal and healthy? Any advice would be helpful.
Tldr, sister never cleans the house and just doesn't care. What can I do?