My older sister was considering moving out. I asked if I could move into that room when she left, but dad said "No, what if she needs a place to crash back on?". Which would be the rule regardless of how long she was gone. We have guest space, we could have moved things around. Either way, she didn't end up moving out because everything is expensive. So here I am. I get to listen to little sister screaming and crying and throwing tantrums as she pleases. I get front row seats. Really angering sometimes, but she usually leaves me alone, fortunately.