R.M.
You don't tell us how old your sister is, or what type of issues she is dealing with. You also don't tell us how you feel about your sister, although just the fact that you are asking this question gives me a fairly good idea.
It sounds to me like this person is causing a lot of stress and anger in your life.Unless you can find a neutral ground ( not your home where she has access to your valuables) to connect with her, I would think you would want to limit your interaction with her.
Do you enjoy the time that you spend with her? If she was an acquaintance, and not a relation, would you continue to seek out her company? Is she dependant upon you for living conditions or support in any way? If the answer to all three of those questions is NO, then I would say move on and try to live your life with as little contact as possible.
Some people are never EVER going to change and it just takes a while for us to come to that realization. My husband has a grown son ( In his forties and a father and grandfather himself) who's family is a constant source of conflict for us. i struggle with feelings of guilt because I feel so much differently towards other members of our family than I do towards him and his immediate family. Everytime they "re-enter" our lives it just manages to reopen all of the issues that have plagued us for years. The only time they contact us is when they need something or want something.
I know that I am much better off, limiting the amount of time an energy that I invest in them and my suspicion is that you are going to find that the same is true with your sister.
Good luck!!