House cleaner: starts being plausible at approximately "$100k/year and really busy". Depends a lot on family circumstances (e.g., two parents working full-time with two children versus childless couple one of whom doesn't have a paid job).

Disagree with this one. Even at a low income I found that having someone come in once a month was definitely worth it. Depends how much you value having a neat house/how much you disvalue cleaning.